Use of 8-amino-aryl-substituted imidazopyrazines as kinase inhibitors

ABSTRACT

The present invention relates to 8-amino-aryl-substituted imidazopyrazines which modulate the activity of protein kinases (“PKs”). The compounds of this invention are therefore useful in treating disorders related to abnormal PK activity. Pharmaceutical compositions comprising these compounds, methods of treating diseases utilizing pharmaceutical compositions comprising these compounds and methods of preparing them are also disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority U.S. Provisional Application No. 60/448,114, filed Feb. 20, 2003, the contents of which are hereby incorporated by reference in their entirety and for all purposes.

FIELD OF INVENTION

The present invention relates to certain 8-amino-aryl-substituted imidazopyrazines which modulate the activity of protein kinases (“PKs”). The compounds of this invention are therefore useful in treating disorders related to abnormal PK activity. Pharmaceutical compositions comprising these compounds, methods of treating diseases utilizing pharmaceutical compositions comprising these compounds and methods of preparing them are also disclosed.

STATE OF THE ART

PKs are enzymes that catalyze the phosphorylation of hydroxy groups on tyrosine, serine and threonine residues of proteins. The consequences of this seemingly simple activity are staggering; cell growth, differentiation and proliferation, i.e., virtually all aspects of cell life in one way or another depend on PK activity. Furthermore, abnormal PK activity has been related to a host of disorders, ranging from relatively non-life threatening diseases such as psoriasis to extremely virulent diseases such as glioblastoma (brain cancer).

The PKs can be conveniently broken down into two classes, the protein tyrosine kinases (PTKs) and the serine-threonine kinases (STKs).

One of the prime aspects of PTK activity is their involvement with growth factor receptors. Growth factor receptors are cell-surface proteins. When bound by a growth factor ligand, growth factor receptors are converted to an active form which interacts with proteins on the inner surface of a cell membrane. This leads to phosphorylation on tyrosine residues of the receptor and other proteins and to the formation inside the cell of complexes with a variety of cytoplasm signaling molecules that, in turn, effect numerous cellular responses such as cell division (proliferation), cell differentiation, cell growth, expression of metabolic effects to the extracellular microenvironment, etc. For a more complete discussion, see Schlessinger and Ullrich, Neuron, 9:303–391 (1992) which is incorporated by reference, including any drawings, as if fully set forth herein.

Growth factor receptors with PTK activity are known as receptor tyrosine kinases (“RTKs”). They comprise a large family of transmembrane receptors with diverse biological activity. At present, at least nineteen (19) distinct subfamilies of RTKs have been identified. An example of these is the subfamily designated the “HER” RTKs, which include EGFR (epithelial growth factor receptor), HER2, HER3 and HER4. These RTKs consist of an extracellular glycosylated ligand binding domain, a transmembrane domain and an intracellular cytoplasm catalytic domain that can phosphorylate tyrosine residues on proteins.

Another RTK subfamily consists of insulin receptor (IR), insulin-like growth factor I receptor (IGF-1R) and insulin receptor related receptor (IRR). IR and IGF-1R interact with insulin, IGF-I and IGF-II to form a heterotetramer of two entirely extracellular glycosylated α subunits and two β subunits which cross the cell membrane and which contain the tyrosine kinase domain.

A third RTK subfamily is referred to as the platelet derived growth factor receptor (“PDGFR”) group, which includes PDGFRα, PDGFRβ, CSFIR, c-kit and c-fms. These receptors consist of glycosylated extracellular domains composed of variable numbers of immunoglobin-like loops and an intracellular domain wherein the tyrosine kinase domain is interrupted by unrelated amino acid sequences.

Another group which, because of its similarity to the PDGFR subfamily, is sometimes subsumed into the later group is the fetus liver kinase (“flk”) receptor subfamily. This group is believed to be made up of kinase insert domain-receptor fetal liver kinase-1 (KDR/FLK-1, VEGF-R2), flk-1R, flk-4 and fms-like tyrosine kinase 1 (flt-1).

A further member of the tyrosine kinase growth factor receptor family is the fibroblast growth factor (“FGF”) receptor subgroup. This group consists of four receptors, FGFR1–4, and seven ligands, FGF1–7. While not yet well defined, it appears that the receptors consist of a glycosylated extracellular domain containing a variable number of immunoglobin-like loops and an intracellular domain in which the tyrosine kinase sequence is interrupted by regions of unrelated amino acid sequences.

Still another member of the tyrosine kinase growth factor receptor family is the vascular endothelial growth factor (VEGF″) receptor subgroup. VEGF is a dimeric glycoprotein similar to PDGF but has different biological functions and target cell specificity in vivo. In particular, VEGF is presently thought to play an essential role is vasculogenesis and angiogenesis.

A more complete listing of the known RTK subfamilies is described in Plowman et al., DN&P, 7(6):334–339 (1994) which is incorporated by reference, including any drawings, as if fully set forth herein.

In addition to the RTKs, there also exists a family of entirely intracellular PTKs called “non-receptor tyrosine kinases” or “cellular tyrosine kinases.” This latter designation, abbreviated “CTK,” will be used herein. CTKs do not contain extracellular and transmembrane domains. At present, over 24 CTKs in 11 subfamilies (Src, Frk, Btk, Csk, Ab1, Zap70, Fes, Fps, Fak, Jak and Ack) have been identified. The Src subfamily appear so far to be the largest group of CTKs and includes Src, Yes, Fyn, Lyn, Lck, Blk, Hck, Fgr and Yrk. For a more detailed discussion of CTKs, see Bolen, Oncogene, 8:2025–2031 (1993), which is incorporated by reference, including any drawings, as if fully set forth herein.

The serine/threonine kinases, STKs, like the CTKs, are predominantly intracellular although there are a few receptor kinases of the STK type. STKs are the most common of the cytosolic kinases; i.e., kinases that perform their function in that part of the cytoplasm other than the cytoplasmic organelles and cytoskelton. The cytosol is the region within the cell where much of the cell's intermediary metabolic and biosynthetic activity occurs; e.g., it is in the cytosol that proteins are synthesized on ribosomes.

RTKs, CTKs and STKs have all been implicated in a host of pathogenic conditions including, significantly, cancer. Other pathogenic conditions which have been associated with PTKs include, without limitation, psoriasis, hepatic cirrhosis, diabetes, angiogenesis, restenosis, ocular diseases, rheumatoid arthritis and other inflammatory disorders, immunological disorders such as autoimmune disease, cardiovascular disease such as atherosclerosis and a variety of renal disorders.

With regard to cancer, two of the major hypotheses advanced to explain the excessive cellular proliferation that drives tumor development relate to functions known to be PK regulated. That is, it has been suggested that malignant cell growth results from a breakdown in the mechanisms that control cell division and/or differentiation. It has been shown that the protein products of a number of proto-oncogenes are involved in the signal transduction pathways that regulate cell growth and differentiation. These protein products of proto-oncogenes include the extracellular growth factors, transmembrane growth factor PTK receptors (RTKs), cytoplasmic PTKs (CTKs) and cytosolic STKs, discussed above.

In view of the apparent link between PK-related cellular activities and wide variety of human disorders, it is no surprise that a great deal of effort is being expended in an attempt to identify ways to modulate PK activity. Some of this effort has involved biomimetic approaches using large molecules patterned on those involved in the actual cellular processes (e.g., mutant ligands (U.S. Pat. No. 4,966,849); soluble receptors and antibodies (application Ser. No. WO 94/10202, Kendall and Thomas, Proc. Nat'l Acad. Sci., 90:10705–09 (1994), Kim, et al., Nature, 362:841–844 (1993)); RNA ligands (Jelinek, et al., Biochemistry, 33:10450–56); Takano, et al., Mol. Bio. Cell 4:358A (1993); Kinsella, et al., Exp. Cell Res. 199:56–62 (1992); Wright, et al., J. Cellular Phys., 152:448–57) and tyrosine kinase inhibitors (WO 94/03427; WO 92/21660; WO 91/15495; WO 94/14808; U.S. Pat. No. 5,330,992; Mariani, et al., Proc. Am. Assoc. Cancer Res., 35:2268 (1994)).

In addition to the above, attempts have been made to identify small molecules which act as PK inhibitors. For example, bis-monocylic, bicyclic and heterocyclic aryl compounds (PCT WO 92/20642), vinyleneazaindole derivatives (PCT WO 94/14808) and 1-cyclopropyl-4-pyridylquinolones (U.S. Pat. No. 5,330,992) have been described as tyrosine kinase inhibitors. Styryl compounds (U.S. Pat. No. 5,217,999), styryl-substituted pyridyl compounds (U.S. Pat. No. 5,302,606), quinazoline derivatives (EP App. No. 0 566 266 A1), selenaindoles and selenides (PCT WO 94/03427), tricyclic polyhydroxylic compounds (PCT WO 92/21660) and benzylphosphonic acid compounds (PCT WO 91/15495) have all been described as PTK inhibitors useful in the treatment of cancer.

SUMMARY OF THE INVENTION

One embodiment of the invention relates to a compound of formula I:

-   wherein R₁ and R₂ are each independently H, alkyl, cycloalkyl, aryl,     heteroaryl, —C(O)R₇, —OR₇ or —C(O)NR₇R₈ wherein the alkyl,     cycloalkyl, aryl and heteroaryl groups may be further substituted     with a substituent selected from the group consisting of aryl,     halogen, —OH, —OR₇, a heteroalicyclic group, and a trihaloalkyl     group; -   R₃ and R₄ are each independently selected from the group consisting     of H, halo, alkyl, aryl, heteroaryl, heteroalicylic, —OH, —OR₇,     —NR₇R₈, —(CH₂)_(n)C(O)OR₇, —SO₂R₇, —(CH₂)_(n)C(O)NR₇R₈, —C(S)NR₇R₈,     —C(O)R₇, —NR₇C(O)R₈, —NHC(O)OR₈, —NR₇C(O)NR₉R₈, —SO₂NR₇R₈,     —OC(O)OR₇, —OC(O)NR₇R₈, CN and NO₂, wherein the alkyl, aryl,     heteroaryl and heteroalicyclic groups may be further substituted     with one or more substitutents selected from the group consisting of     alkyl, alkoxy, halogen, hydroxy or protected hydroxy, —OR₇, —NR₇R₈,     —NR₇C(O)R₈, aryl, —C(O)OR₇, cycloalkyl, haloalkyl, haloalkoxy,     —C(O)R₇, —NR₇C(O)OR₈, —SO₂R₇, —NR₇C(O)NR₉R₈, —C(O)NR₇R₈ and     —SO₂NR₇R₈; -   R₅ is selected from the group consisting of H, aryl, or halo,     wherein the aryl group may be further substituted with one or more     substitutents selected from the group consisting of alkyl, alkoxy,     halogen, hydroxy or protected hydroxy, —OR₇, —NR₇R₈, —NR₇C(O)R₈,     aryl, —C(O)OR₇, cycloalkyl, haloalkyl, haloalkoxy, —C(O)R₇,     —NR₇C(O)OR₈, —SO₂R₇, —NR₇C(O)NR₉R₈, —C(O)NR₇R₈ and —SO₂NR₇R₈; -   wherein at least one of R₃, R₄ and R₅ is an aryl; -   R₆ is H; -   R₇, R₈ and R₉ are independently H, alkyl, aralkyl, heterocycloalkyl     or aryl, wherein the alkyl and aryl may be further substituted with     a substituent selected from the group consisting of alkyl, aryl,     trifluoroalkyl, —OH, alkoxy, amino, —NO₂ and —CN; -   alternatively, NR₇R₈ can form a 5–7 membered heteroalicyclic ring, a     5–6 membered heteroaryl ring, wherein the heteroalicyclic ring may     further contain no more than 4 of the heteroatoms (N, O, or S), and     the cyclic structure formed about NR₇R₈ may be substituted with a     substitutent selected from the group consisting of alkyl, haloalkyl,     alkoxy, heteroalicylic, aryl, heteroaryl and halo; and -   wherein n=0–3; -   or a pharmaceutically acceptable salt thereof.

Another embodiment relates to a compound of the formula I:

-   wherein R₁ and R₂ are each independently H, alkyl, cycloalkyl, aryl,     heteroaryl, —C(O)R₇, —OR₇ or —C(O)NR₇R₈ wherein the alkyl,     cycloalkyl, aryl and heteroaryl groups may be further substituted     with a substituent selected from the group consisting of aryl,     halogen, —OH, —OR₇, a heteroalicyclic group, and a trihaloalkyl     group; -   R₃ and R₄ are each H; -   R₅ is aryl, wherein the aryl group may be further substituted with     one or more substitutents selected from the group consisting of     alkyl, alkoxy, halogen, hydroxy or protected hydroxy, —OR₇, —NR₇R₈,     —NR₇C(O)R₈, aryl, —C(O)OR₇, cycloalkyl, haloalkyl, haloalkoxy,     —C(O)R₇, —NR₇C(O)OR₈, —SO₂R₇, —NR₇C(O)NR₉R₈, —C(O)NR₇R₈ and     —SO₂NR₇R₈; -   R₆ is H; -   R₇, R₈ and R₉ are independently H, alkyl or aryl, wherein the alkyl     and aryl may be further substituted with a substituent selected from     the group consisting of alkyl, aryl, trifluoroalkyl, —OH, alkoxy,     amino, —NO₂ and —CN; -   alternatively, NR₇R₈ can form a 5–7 membered heteroalicyclic ring, a     5–6 membered heteroaryl ring, wherein the heteroalicyclic ring may     further contain no more than four heteroatoms (N, O, or S), and the     cyclic structure formed about NR₇R₈ may be substituted with a     substitutent selected from the group consisting of alkyl, haloalkyl,     alkoxy, heteroalicylic, aryl, heteroaryl and halo; and -   wherein n=0–3; -   or a pharmaceutically acceptable salt thereof.

In a further embodiment of the invention are compounds of formula I:

-   wherein R₁ and R₂ are each independently H, alkyl, cycloalkyl, aryl,     heteroaryl, —C(O)R₇, —OR₇ or —C(O)NR₇R₈ wherein the alkyl,     cycloalkyl, aryl and heteroaryl groups may be further substituted     with a substituent selected from the group consisting of aryl,     halogen, —OH, —OR₇, a heteroalicyclic group, and a trihaloalkyl     group; -   R₃ is aryl, wherein the aryl group may be further substituted with     one or more substitutents selected from the group consisting of     alkyl, alkoxy, halogen, hydroxy or protected hydroxy, —OR₇, —NR₇R₈,     —NR₇C(O)R₈, aryl, —C(O)OR₇, cycloalkyl, haloalkyl, haloalkoxy,     —C(O)R₇, —NR₇C(O)OR₈, —SO₂R₇, —NR₇C(O)NR₉R₈, —C(O)NR₇R₈ and     —SO₂NR₇R₈; -   R₄ is H; -   R₅ is selected from the group consisting of H, aryl or halo, wherein     the aryl group may be further substituted with one or more     substitutents selected from the group consisting of alkyl, alkoxy,     halogen, hydroxy or protected hydroxy, —OR₇, —NR₇R₈, —NR₇C(O)R₈,     aryl, —C(O)OR₇, cycloalkyl, haloalkyl, haloalkoxy, —C(O)R₇,     —NR₇C(O)OR₈, —SO₂R₇, —NR₇C(O)NR₉R₈, —C(O)NR₇R₈ and —SO₂NR₇R₈; -   R₆ is H; -   R₇, R₈ and R₉ are independently H, alkyl or aryl, wherein the alkyl     and aryl may be further substituted with a substituent selected from     the group consisting of alkyl, aryl, trifluoroalkyl, —OH, alkoxy,     amino, —NO₂ and —CN; -   alternatively, NR₇R₈ can form a 5–7 membered heteroalicyclic ring, a     5–6 membered heteroaryl ring, wherein the heteroalicyclic ring may     further contain no more than four heteroatoms (N, O, or S), and the     cyclic structure formed about NR₇R₈ may be substituted with a     substitutent selected from the group consisting of alkyl, haloalkyl,     alkoxy, heteroalicylic, aryl, heteroaryl and halo; and -   wherein n=0–3; -   or a pharmaceutically acceptable salt thereof.

In yet another embodiment of the invention are compounds of formula I:

-   wherein R₁ and R₂ are each independently H, alkyl, cycloalkyl, aryl,     heteroaryl, —C(O)R₇, —OR₇ or —C(O)NR₇R₈ wherein the alkyl,     cycloalkyl, aryl and heteroaryl groups may be further substituted     with a substituent selected from the group consisting of aryl,     halogen, —OH, —OR₇, a heteroalicyclic group, and a trihaloalkyl     group; -   R₃ is H; -   R₄ is aryl, wherein the aryl group may be further substituted with     one or more substitutents selected from the group consisting of     alkyl, alkoxy, halogen, hydroxy or protected hydroxy, —OR₇, —NR₇R₈,     —NR₇C(O)R₈, aryl, —C(O)OR₇, cycloalkyl, haloalkyl, haloalkoxy,     —C(O)R₇, —NR₇C(O)OR₈, —SO₂R₇, —NR₇C(O)NR₉R₈, —C(O)NR₇R₈ and     —SO₂NR₇R₈; -   R₅ is selected from the group consisting of H, aryl or halo, wherein     the aryl group may be further substituted with one or more     substitutents selected from the group consisting of alkyl, alkoxy,     halogen, hydroxy or protected hydroxy, —OR₇, —NR₇R₈, —NR₇C(O)R₈,     aryl, —C(O)OR₇, cycloalkyl, haloalkyl, haloalkoxy, —C(O)R₇,     —NR₇C(O)OR₈, —SO₂R₇, —NR₇C(O)NR₉R₈, —C(O)NR₇R₈ and —SO₂NR₇R₈; -   R₆ is H; -   R₇, R₈ and R₉ are independently H, alkyl or aryl, wherein the alkyl     and aryl may be further substituted with a substituent selected from     the group consisting of alkyl, aryl, trifluoroalkyl, hydroxy,     alkoxy, amino, —NO₂ and —CN; -   alternatively, NR₇R₈ can form a 5–7 membered heteroalicyclic ring, a     5–6 membered heteroaryl ring, wherein the heteroalicyclic ring may     further contain no more than four heteroatoms (N, O, or S), and the     cyclic structure formed about NR₇R₈ may be substituted with a     substitutent selected from the group consisting of alkyl, haloalkyl,     alkoxy, hydroxy, heteroalicylic, heterocycloalkyl, aryl, heteroaryl,     aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl and halo; and -   wherein n=0–3; -   or a pharmaceutically acceptable salt thereof.

In a one embodiment of the present invention, R₄ and R₅ are optionally substituted aryl in the compounds of formula I.

Preferred examples of compounds of formula (I) include, but are not limited to one of the following:

-   Methyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   3-Phenyl-imidazo[1,2-a]pyrazin-8-ylamine, -   3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-ylamine, -   N-[4-(4-trifluoromethyl-benzamide-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-4-trifluoromethyl-benzamide, -   N-[4-(8-Amino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-4-trifluoromethyl-benzamide, -   (4-Methoxy-phenyl)-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   Dimethyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   Isopropyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   4-(8-Isopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   Butyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   Ethyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   (2-Morpholin-4-yl-ethyl)-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   Benzyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   2-(3-Phenyl-imidazo[1,2-a]pyrazin-8-ylamino)-ethanol, -   1-Butyl-3-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-urea, -   N-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-acetamide, -   N-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-acetamide, -   2,6-Dimethyl-4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   3-(4-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-ylamine, -   Cyclopropyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   [3-(4-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Methyl-[3-(2-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   Methyl-[3-(3-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   Methyl-[3-(2-phenoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   (3-Biphenyl-2-yl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine, -   [3-(2-Benzyloxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone, -   [3-(3-Isopropyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(4-tert-Butyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(4-Cyclohexyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(3,5-Bis-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-benzoic acid, -   3-(8-Methylamino-imidazo[1,2-a]pyrazin-4-yl)-benzoic acid, -   Methyl-(3-o-tolyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   [4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-carbamic acid     benzyl ester, -   Methyl-[3-(4-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   [3-(2,4-Difluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(3,4-Dichloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(3-Fluoro-4-methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   (3-Biphenyl-4-yl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine, -   (3-Biphenyl-3-yl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine, -   [3-(4-Benzyloxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Methyl-(3-naphthalen-1-yl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   [3-(2-Chloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   N-[3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]acetamide, -   Methyl-[3-(2-trifluoromethoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   Methyl-[3-(3-trifluoromethoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   Cyclopropyl-{3-[3-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine, -   3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   Methyl-[3-(4-trifluoromethoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   [3-(2-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(3,4-Difluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   (3-Benzo[1,3]dioxol-5-yl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine, -   [3-(3-Chloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(4-Methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(2-Methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Methyl-[3-(4-phenoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   [3-(4-Benzyloxy-3-fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(4-Isopropyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(3,5-Bis-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, -   Cyclopropyl-[3-(3,4-dichloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-benzoic acid, -   Methyl-{3-[4-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine, -   Cyclopropyl-{3-[4-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine, -   Cyclopropyl-[3-(4-dimethylamino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   Cyclopropyl-[3-(4-phenoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone, -   [4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-carbamic     acid benzyl ester, -   N-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-acetamide, -   [3-(3-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, -   [3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Methyl-(3-naphthalen-2-yl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-benzoic acid, -   [3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, -   Methyl-{3-[3-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine, -   [3-(3-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-N-(2-morpholin-4-yl-ethyl)-benzamide, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-N-(3-morpholin-4-yl-propyl)-benzamide, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-N-(3-pyrrolidin-1-yl-propyl)-benzamide, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (S)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (S)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   (S)-3-Hydroxy-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[3-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, -   4-Pyrrolidin-1-yl-piperidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, -   4-Hydroxy-piperidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide -   (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[3-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   4-Hydroxy-piperidine-1-carboxylic     acid[3-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (R)-2-Dimethylaminomethyl-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea, -   (R)-3-Hydroxy-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, -   [5-(4-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Methyl-(5-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   Methyl-(5-thiophen-3-yl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-5-yl)-phenol, -   N-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-5-yl)-phenyl]-acetamide, -   [3,5-Bis-(4-fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   (3,5-Diphenyl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine, -   Methyl-(6-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-6-yl)-phenol, -   6-Phenyl-imidazo[1,2-a]pyrazin-8-ylamine and -   Dimethyl-(3-phenyl-imidazo[1,2-a]pyrazin-5-yl-amine, -   or a prodrug or pharmaceutically acceptable salt thereof. -   Preferred compounds of the present invention include the following: -   Methyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   Ethyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   Cyclopropyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone, -   [4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-carbamic acid     benzyl ester, -   [3-(3-Fluoro-4-methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   Methyl-[3-(4-trifluoromethoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   [3-(4-Benzyloxy-3-fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Cyclopropyl-[3-(4-dimethylamino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone, -   [4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-carbamic     acid benzyl ester, -   [3-(3-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, -   [3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Methyl-(3-naphthalen-2-yl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   [3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, -   [3-(3-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (S)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (S)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   (S)-3-Hydroxy-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[3-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, -   4-Pyrrolidin-1-yl-piperidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylarnino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, -   4-Hydroxy-piperidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea, -   (R)-3-Hydroxy-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea     and -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, -   or a prodrug or pharmaceutically acceptable salt thereof.

The present invention contemplates a pharmaceutical composition, comprising a compound, of Formula (I) and a pharmaceutically acceptable carrier or excipient.

The present invention also encompassed a method for the modulation of the catalytic activity of a protein kinase comprising contacting the protein kinase with a compound, or a pharmaceutically acceptable salt of a compound of Formula (I).

In the method of modulation of catalytic acivitity of a protein kinase, the protein kinase is selected from the group consisting of a receptor tyrosine kinase, a non-receptor tyrosine kinase and a serine-threonine kinase.

The present invention also contemplates a method for treating or preventing a protein kinase related disorder in an organism comprising administering a therapeutically effective amount of a pharmaceutical composition comprising a compound, or a pharmaceutically acceptable salt of a compound of formula (I) and a pharmaceutically acceptable carrier or excipient to the organism.

In the another embodiment of the inventive method of treating or preventing a protein kinase related disorder in an organism, the protein kinase related disorder is selected from the group consisting of a receptor tyrosine kinase related disorder, a non-receptor tyrosine kinase related disorder and a serine-threonine kinase related disorder.

In another embodiment of the inventive method of treating or preventing a protein kinase related disorder in an organism, the protein kinase related disorder is selected from the group consisting of an PDGFR related disorder and a flk related disorder.

In another embodiment of the inventive method of treating or preventing a protein kinase related disorder in an organism, the protein kinase related disorder is a cancer selected from the group consisting of squamous cell carcinoma, astrocytoma, Kaposi's sarcoma, glioblastoma, lung cancer, bladder cancer, head and neck cancer, melanoma, ovarian cancer, prostate cancer, breast cancer, small-cell lung cancer, glioma, colorectal cancer, genitourinary cancer and gastrointestinal cancer.

In another embodiment of the inventive method of treating or preventing a protein kinase related disorder in an organism, the protein kinase related disorder is selected from the group consisting of diabetes, an autoimmune disorder, a hyperproliferation disorder, restenosis, fibrosis (including pulmonary fibrosis), psoriasis, von Heppel-Lindau disease, osteoarthritis, rheumatoid arthritis, angiogenesis, an inflammatory disorder, an immunological disorder and a cardiovascular disorder.

In a preferred embodiment of the inventive methods, the organism treated is a human.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Definitions

Unless otherwise stated the following terms used in the specification and claims have the meanings discussed below:

-   “8-amino-imidazopyrazine” refers to a molecule having the chemical     structure:

“Pharmaceutically acceptable salt” or “pharmaceutically acceptable salt thereof” refers to those salts which retain the biological effectiveness and properties of the free bases and which are obtained by reaction with inorganic or organic acids, such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, acetic acid, benzenesulfonic acid (besylate), benzoic acid, camphorsulfonic acid, citric acid, fumaric acid, gluconic acid, glutamic acid, isethionic acid, lactic acid, maleic acid, malic acid, mandelic acid, mucic acid, pamoic acid, pantothenic acid, succinic acid, tartaric acid, and the like.

A “pharmaceutical composition” refers to a mixture of one or more of the compounds described herein, or pharmaceutically acceptable salts thereof, with other chemical components, such as pharmaceutically acceptable carriers and excipients. The purpose of a pharmaceutical composition is to facilitate administration of a compound to an organism.

As used herein, a “pharmaceutically acceptable carrier” refers to a carrier or diluent that does not cause significant irritation to an organism and does not abrogate the biological activity and properties of the administered compound.

An “excipient” refers to an inert substance added to a pharmaceutical composition to fuirther facilitate administration of a compound. Examples, without limitation, of excipients include calcium carbonate, calcium phosphate, various sugars and types of starch, cellulose derivatives (including microcrystalline cellulose), gelatin, vegetable oils, polyethylene glycols, diluents, granulating agents, lubricants, binders, disintegrating agents, and the like.

“Alkyl” refers to a saturated aliphatic hydrocarbon including straight chain, branched chain or cyclic groups. Preferably, the alkyl group has 1 to 20 carbon atoms (whenever a numerical range; e.g., “1–20”, is stated herein, it means that the group, in this case the alkyl group, may contain 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc. up to and including 20 carbon atoms). More preferably, it is a medium size alkyl having 1 to 10 carbon atoms. Most preferably, it is a lower alkyl having 1 to 4 carbon atoms. The alkyl group may be substituted or unsubstituted. When substituted, each substituent group is preferably one or more individually selected from halogen, -hydroxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO₂, —CZ₃, —SR′, —SOR′, —SO₂R′, —SO₂OR′, —SO₂NRR′, thiocarbonyl, —RNSO₂R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl. R and R′ are independently H, alkyl, or aryl, wherein alkyl or aryl may be further substituted with halogen, (CH₂)_(n)N(R″)₂, (CH₂)_(n)CO₂R″, (CH₂)_(n)OR″, (CH₂)_(n)OC(O)R″, alkoxycarbonyl, aryloxycarbonyl, aminocarbonyl, a heteroalicyclic ring, aryl, alkoxy, —OCZ₃, aryloxy, C(O)NH₂ or heteroaryl. R″ is H, alkyl or aryl and n is 0–3.

“Alkenyl” refers to an aliphatic hydrocarbon having at least one carbon-carbon double bond, including straight chain, branched chain or cyclic groups having at least one carbon-carbon double bond. Preferably, the alkenyl group has 2 to 20 carbon atoms (whenever a numerical range; e.g., “2–20”, is stated herein, it means that the group, in this case the alkenyl group, may contain 2 carbon atoms, 3 carbon atoms, etc. up to and including 20 carbon atoms). More preferably, it is a medium size alkenyl having 2 to 10 carbon atoms. Most preferably, it is a lower alkenyl having 2 to 6 carbon atoms. The alkenyl group may be substituted or unsubstituted. When substituted, each substituent group is preferably one or more individually selected from halogen,-hydroxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO₂, —CZ₃, —SR′, —SOR′, —SO₂R′, —SO₂OR′, —SO₂NRR′, thiocarbonyl, —RNSO₂R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl, wherein R and R′ are defined herein.

“Alkynyl” refers to an aliphatic hydrocarbon having at least one carbon-carbon triple bond, including straight chain, branched chain or cyclic groups having at least one carbon-carbon triple bond. Preferably, the alkenyl group has 2 to 20 carbon atoms (whenever a numerical range; e.g., “2–20”, is stated herein, it means that the group, in this case the alkynyl group, may contain 2 carbon atoms, 3 carbon atoms, etc. up to and including 20 carbon atoms). More preferably, it is a medium size alkynyl having 2 to 10 carbon atoms. Most preferably, it is a lower alkynyl having 2 to 6 carbon atoms. The alkynyl group may be substituted or unsubstituted. When substituted, each substituent group is preferably one or more individually selected from halogen, -hydroxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO₂, —CZ₃, —SR′, —SOR′, —SO₂R′, —SO₂OR′, —SO₂NRR′, thiocarbonyl, —RNSO₂R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl, wherein R and R′ are defined herein.

A “cycloalkyl” group refers to an all-carbon monocyclic or fused ring (i.e., rings which share an adjacent pair of carbon atoms) group wherein one of more of the rings does not have a completely conjugated pi-electron system. Examples, without limitation, of cycloalkyl groups are cyclopropane, cyclobutane, cyclopentane, cyclopentene, cyclohexane, adamantane, cyclohexadiene, cycloheptane and, cycloheptatriene. A cycloalkyl group may be substituted or unsubstituted. When substituted, each substituent group is preferably one or more individually selected from halogen, -hydroxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO₂, —CZ₃, —SR′, —SOR′, —SO₂R′, —SO₂OR′, —SO₂NRR′, thiocarbonyl, —RNSO₂R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl, wherein R and R′ are defined herein.

An “aryl” group refers to an all-carbon monocyclic or fused-ring polycyclic (i.e., rings which share adjacent pairs of carbon atoms) groups having a completely conjugated pi-electron system. Examples, without limitation, of aryl groups are phenyl, naphthalenyl and anthracenyl. The aryl group may be substituted or unsubstituted. When substituted, each substituted group is preferably one or more selected halogen, hydroxy, alkoxy, aryloxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO₂, —CZ₃, —OCZ₃, —SR′, —SOR′, —SO₂R′, —SO₂OR′, —SO₂NRR′, thiocarbonyl, —RNSO₂R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl, wherein R and R′ are defined herein.

An “aralkyl” group refers to an aryl group bonded to an alkyl moiety. Examples, without limitation, include benzyl and ethylbenzene. The aralkyl group may be substituted or unsubstituted. When substituted, each substituted group is preferably one or more selected halogen, hydroxy, alkoxy, aryloxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO₂, —CZ₃, —OCZ₃, —SR′, —SOR′, —SO₂R′, —SO₂OR′, —SO₂NRR′, thiocarbonyl, —RNSO₂R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl, wherein R and R′ are defined herein.

As used herein, a “heteroaryl” group refers to a monocyclic or fused ring (i.e., rings which share an adjacent pair of atoms) group having in the ring(s) one or more atoms selected from the group consisting of nitrogen, oxygen and sulfur and, in addition, having a completely conjugated pi-electron system. Examples, without limitation, of heteroaryl groups are pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrimidine, quinoline, isoquinoline, purine and carbazole. The heteroaryl group may be substituted or unsubstituted. When substituted, each substituted group is preferably one or more selected from halogen, -hydroxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO₂, —CZ₃, —SR′, —SOR′, —SO₂R′, —SO₂OR′, —SO₂NRR′, thiocarbonyl, —RNSO₂R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl, where Z is halogen, wherein R and R′ are defined herein.

A “heteroalicyclic ring” or “heteroalicycle” group refers to a monocyclic or fused ring group having in the ring(s) one or more atoms selected from the group consisting of nitrogen, oxygen and sulfur. The rings may also have one or more double bonds. However, the rings may not have a completely conjugated pi-electron system. The heteroalicyclic ring may be substituted or unsubstituted. The heteroalicyclic ring may contain one or more oxo groups. When substituted, the substituted group(s) is preferably one or more selected halogen, hydroxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO₂, —CZ₃, —SR′, —SOR′, —SO₂R′, —SO₂OR′, —SO₂NRR′, thiocarbonyl, —RNSO₂R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl, wherein R and R′ are defined herein. A heteroalicylic group that is not contemplated in the preferred embodiments of the present invention is 4,5-dihydro-1H-imidazole.

A “heteroalicycloalkyl” group refers to a heteroalicyclic ring bonded to an alkyl moiety. Examples include without limitation —CH₂-morpholinyl, —CH₂—CH₂-pyrrolidinyl and —CH₂-piperazinyl. The heteroalicycloalkyl group may be substituted or unsubstituted. When substituted, each substituted group is preferably one or more selected halogen, hydroxy, alkoxy, aryloxy, —COR′, —COOR′, OCOR′, —CONRR′, —RNCOR′, —NRR′, —CN, —NO₂, —CZ₃, —OCZ₃, —SR′, —SOR′, —SO₂R′, —SO₂OR′, —SO₂NRR′, thiocarbonyl, —RNSO₂R′, perfluoroalkyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, silyl, ammonium, lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl, heteroalicycle, heteroaryl and aryl, wherein R and R′ are defined herein.

Z refers to a halogen group selected from the group consisting of fluorine, chlorine, bromine and iodine.

A “hydroxy” group refers to an —OH group.

A “protected hydroxy” group refers to a —OR, where the R is a protecting group, with a diol substituted compound a single protecting group can be used to form, e.g., a dioxolone (e.g.,

An “alkoxy” group refers to both an —O-alkyl and an —O-cycloalkyl group, as defined herein.

An “alkoxycarbonyl” refers to a —C(O)—OR.

An “aminocarbonyl” refers to a —C(O)—NRR′.

An “aryloxycarbonyl” refers to —C(O)—Oaryl.

An “aryloxy” group refers to both an —O-aryl and an —O-heteroaryl group, as defined herein.

An “arylalkyl” group refers to -alkyl-aryl, where alkyl and aryl are defined herein.

An “arylsulfonyl” group refers to a —S(O)n-aryl, wherein n is 0–2.

An “alkylsulfonyl” group refer to a —S(O)n-alkyl, wherein n is 0–2.

A “heteroaryloxyl” group refers to a heteroaryl-O— group with heteroaryl as defined herein.

A “heteroalicycloxy” group refers to a heteroalicyclic-O— group with heteroalicyclic as defined herein.

A “carbonyl” group refers to a —C(═O).

An “aldehyde” group refers to —C(═O)—R group where R is hydrogen.

A “thiocarbonyl” group refers to a —C(═S)—R group.

A “trihalomethanecarbonyl” group refers to a Z₃C—C(O)— group.

A “C-carboxyl” group refers to a —C(O)O—R groups.

An “O-carboxyl” group refers to a R—C(O)O— group.

A “carboxylic acid” group refers to a C-carboxyl group in which R is hydrogen.

A “halo” or “halogen” group refers to fluorine, chlorine, bromine or iodine.

A “trihalomethyl” or a “trihaloalkyl” group refers to a —(CZ₂)_(n)—CZ₃ group, where n is 0 or greater.

A “trihalomethanesulfonyl” group refers to a Z₃CS(O)₂ group.

A “trihalomethanesulfonamido” group refers to a Z₃CS(O)₂NR— group.

A “sulfinyl” group refers to a —S(O)—R group.

A “sulfonyl” group refers to a —S(O)₂R group.

An “S-sulfonamido” group refers to a —S(O)₂NRR′ group.

An “N-Sulfonamido” group refers to a —NR—S(O)₂R group.

An “O-carbamyl” group refers to a —OC(O)NRR′ group.

An “N-carbamyl” group refers to a ROC(O)NRR′ group.

An “O-thiocarbamyl” group refers to a —OC(S)NRR′ group.

An “N-thiocarbamyl” group refers to a ROC(S)NR′— group.

An “amino” group refers to an —NH₂ or an —NRR′ group.

A “C-amido” group refers to a —C(O)NRR′ group.

An “N-amido” group refers to a R′C(O)NR— group.

A “nitro” group refers to a —NO₂ group.

A “cyano” group refers to a —CN group.

A “silyl” group refers to a —Si(R)₃ group.

A “phosphonyl” group refers to a P(═O)(OR)₂ group.

Compounds that have the same molecular formula but differ in the nature or sequence of bonding of their atoms or the arrangement of their atoms in space are termed “isomers”. Isomers that differ in the arrangement of their atoms in space are termed “stereoisomers.”

Stereoisomers that are not mirror images of one another are termed “diastereomers” and those that are non-superimposable mirror images of each other are termed “enantiomers”. When a compound has an asymmetric center, for example, it is bonded to four different groups, a pair of enantiomers is possible. An enantiomer can be characterized by the absolute configuration of its asymmetric center and is described by the R- and S-sequencing rules of Cahn and Prelog, or by the manner in which the molecule rotates the plane of polarized light and designated as dextrorotatory or levorotatory (i.e., as (+) or (−)-isomers respectively). A chiral compound can exist as either individual enantiomer or as a mixture thereof. A mixture containing equal proportions of the enantiomers is called a “racemic mixture”.

The compounds of this invention may possess one or more asymmetric centers; such compounds can therefore be produced as individual (R)- or (S)-stereoisomers or as mixtures thereof. Unless indicated otherwise, the description or naming of a particular compound in the specification and claims is intended to include both individual enantiomers and mixtures, racemic or otherwise, thereof. The methods for the determination of stereochemistry and the separation of stereoisomers are well-known in the art (see discussion in Chapter 4 of “Advanced Organic Chemistry”, 4th edition J. March, John Wiley and Sons, New York, 1992).

The compounds of Formula (I) may exhibit the phenomena of tautomerism and structural isomerism. For example, the compounds described herein may adopt an E or a Z configuration about any double bond in the molecule. This invention encompasses any tautomeric or structural isomeric form and mixtures thereof which possess the ability to modulate RTK, CTK and/or STK activity and is not limited to any one tautomeric or structural isomeric form.

A “pharmaceutical composition” refers to a mixture of one or more of the compounds described herein, or physiologically/pharmaceutically acceptable salts or prodrugs thereof, with other chemical components, such as physiologically/pharmaceutically acceptable carriers and excipients. The purpose of a pharmaceutical composition is to facilitate administration of a compound to an organism.

The compound of Formula (I) may also act as a prodrug. A “prodrug” refers to an agent which is converted into the parent drug in vivo. Prodrugs are often useful because, in some situations, they may be easier to administer than the parent drug. They may, for instance, be bioavailable by oral administration whereas the parent drug is not. The prodrug may also have improved solubility in pharmaceutical compositions over the parent drug. An example, without limitation, of a prodrug would be a compound of the present invention which is administered as an ester (the “prodrug”) to facilitate transmittal across a cell membrane where water solubility is detrimental to mobility but then is metabolically hydrolyzed to the carboxylic acid, the active entity, once inside the cell where water solubility is beneficial.

A further example of a prodrug might be a short polypeptide, for example, without limitation, a 2–10 amino acid polypeptide, bonded through a terminal amino group to a carboxy group of a compound of this invention wherein the polypeptide is hydrolyzed or metabolized in vivo to release the active molecule. The prodrugs of a compound of Formula (I) are within the scope of this invention.

Additionally, it is contemplated that a compound of Formula (I) would be metabolized by enzymes in the body of the organism such as a human being to generate a metabolite that can modulate the activity of the protein kinases. Such metabolites are within the scope of the present invention.

As used herein, a “physiologically/pharmaceutically acceptable carrier” refers to a carrier or diluent that does not cause significant irritation to an organism and does not abrogate the biological activity and properties of the administered compound.

An “pharmaceutically acceptable excipient” refers to an inert substance added to a pharmaceutical composition to further facilitate administration of a compound. Examples, without limitation, of excipients include calcium carbonate, calcium phosphate, various sugars and types of starch, cellulose derivatives, gelatin, vegetable oils and polyethylene glycols.

A general definition of“pharmaceutically acceptable salt” is set forth above. Furthermore, the term refers to those salts which retain the biological effectiveness and properties of the parent compound. Such salts include:

(1) acid addition salt which is obtained by reaction of the free base of the parent compound with inorganic acids such as hydrochloric acid, hydrobromic acid, nitric acid, phosphoric acid, sulfuric acid, and perchloric acid and the like, or with organic acids such as acetic acid, oxalic acid, (D) or (L) malic acid, maleic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, tartaric acid, citric acid, succinic acid or malonic acid and the like, preferably hydrochloric acid or (L)-malic; or

(2) salts formed when an acidic proton present in the parent compound either is replaced by a metal ion, e.g., an alkali metal ion, an alkaline earth ion, or an aluminum ion; or coordinates with an organic base such as ethanolamine, diethanolamine, triethanolamine, tromethamine, N-methylglucamine, and the like.

“PK” refers to receptor protein tyrosine kinase (RTKs), non-receptor or “cellular” tyrosine kinase (CTKs) and serine-threonine kinases (STKs).

“Method” refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by, practitioners of the chemical, pharmaceutical, biological, biochemical and medical arts.

“Modulation” or “modulating” refers to the alteration of the catalytic activity of RTKs, CTKs and STKs. In particular, modulating refers to the activation of the catalytic activity of RTKs, CTKs and STKs, preferably the activation or inhibition of the catalytic activity of RTKs, CTKs and STKs, depending on the concentration of the compound or salt to which the RTK, CTK or STK is exposed or, more preferably, the inhibition of the catalytic activity of RTKs, CTKs and STKs.

“Catalytic activity” refers to the rate of phosphorylation of tyrosine under the influence, direct or indirect, of RTKs and/or CTKs or the phosphorylation of serine and threonine under the influence, direct or indirect, of STKs.“Contacting” refers to bringing a compound of this invention and a target PK together in such a manner that the compound can affect the catalytic activity of the PK, either directly, i.e., by interacting with the kinase itself, or indirectly, i.e., by interacting with another molecule on which the catalytic activity of the kinase is dependent. Such “contacting” can be accomplished “in vitro,” i.e., in a test tube, a petri dish or the like. In a test tube, contacting may involve only a compound and a PK of interest or it may involve whole cells. Cells may also be maintained or grown in cell culture dishes and contacted with a compound in that environment. In this context, the ability of a particular compound to affect a PK related disorder, i.e., the IC₅₀ of the compound, defined below, can be determined before use of the compounds in vivo with more complex living organisms is attempted. For cells outside the organism, multiple methods exist, and are well-known to those skilled in the art, to get the PKs in contact with the compounds including, but not limited to, direct cell microinjection and numerous transmembrane carrier techniques.

“In vitro” refers to procedures performed in an artificial environment such as, e.g., without limitation, in a test tube or culture medium.

“In vivo” refers to procedures performed within a living organism such as, without limitation, a mouse, rat or rabbit.

“PK related disorder,” “PK driven disorder,” and “abnormal PK activity” all refer to a condition characterized by inappropriate, i.e., under or, more commonly, over, PK catalytic activity, where the particular PK can be an RTK, a CTK or an STK. Inappropriate catalytic activity can arise as the result of either: (1) PK expression in cells which normally do not express PKs, (2) increased PK expression leading to unwanted cell proliferation, differentiation and/or growth, or, (3) decreased PK expression leading to unwanted reductions in cell proliferation, differentiation and/or growth. Over-activity of a PK refers to either amplification of the gene encoding a particular PK or production of a level of PK activity which can correlate with a cell proliferation, differentiation and/or growth disorder (that is, as the level of the PK increases, the severity of one or more of the symptoms of the cellular disorder increases). Under-activity is, of course, the converse, wherein the severity of one or more symptoms of a cellular disorder increase as the level of the PK activity decreases.

“Treat”, “treating” and “treatment” refer to a method of alleviating or abrogating a PK mediated cellular disorder and/or its attendant symptoms. With regard particularly to cancer, these terms simply mean that the life expectancy of an individual affected with a cancer will be increased or that one or more of the symptoms of the disease will be reduced.

“Organism” refers to any living entity comprised of at least one cell. A living organism can be as simple as, for example, a single eukariotic cell or as complex as a mammal, including a human being.

“Therapeutically effective amount” refers to that amount of the compound being administered which will relieve to some extent one or more of the symptoms of the disorder being treated. In reference to the treatment of cancer, a therapeutically effective amount refers to that amount which has the effect of:

-   (1) reducing the size of the tumor; -   (2) inhibiting (that is, slowing to some extent, preferably     stopping) tumor metastasis; -   (3) inhibiting to some extent (that is, slowing to some extent,     preferably stopping) tumor growth, and/or, -   (4) relieving to some extent (or, preferably, eliminating) one or     more symptoms associated with the cancer.

“Monitoring” means observing or detecting the effect of contacting a compound with a cell expressing a particular PK. The observed or detected effect can be a change in cell phenotype, in the catalytic activity of a PK or a change in the interaction of a PK with a natural binding partner. Techniques for observing or detecting such effects are well-known in the art.

The above-referenced effect is selected from a change or an absence of change in a cell phenotype, a change or absence of change in the catalytic activity of the protein kinase or a change or absence of change in the interaction of the protein kinase with a natural binding partner in a final aspect of this invention.

“Cell phenotype” refers to the outward appearance of a cell or tissue or the biological function of the cell or tissue. Examples, without limitation, of a cell phenotype are cell size, cell growth, cell proliferation, cell differentiation, cell survival, apoptosis, and nutrient uptake and use. Such phenotypic characteristics are measurable by techniques well-known in the art.

“Natural binding partner” refers to a polypeptide that binds to a particular PK in a cell. Natural binding partners can play a role in propagating a signal in a PK-mediated signal transduction process. A change in the interaction of the natural binding partner with the PK can manifest itself as an increased or decreased concentration of the PK/natural binding partner complex and, as a result, in an observable change in the ability of the PK to mediate signal transduction.

Preferred Embodiments

While the broadest definition is set forth in the Summary of the Invention, certain compounds of Formula (I) set forth below are preferred.

A preferred group of compounds of Formula (I) is that wherein R₅ is aryl.

Another preferred group of compounds of Formula (I) is that wherein R₃ is aryl.

Another preferred group of compounds of Formula (I) is that wherein R₄ is aryl.

Another preferred group of compounds of Formula (I) is that wherein both R₄ and R₅ are aryl.

Another preferred group of compounds of Formula (I) are selected from the group consisting of:

-   Methyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   3-Phenyl-imidazo[1,2-a]pyrazin-8-ylamine, -   3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-ylamine, -   N-[4-(4-trifluoromethyl-benzamide-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-4-trifluoromethyl-benzamide, -   N-[4-(8-Amino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-4-trifluoromethyl-benzamide, -   (4-Methoxy-phenyl)-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   Dimethyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   Isopropyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   4-(8-Isopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   Butyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   Ethyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   (2-Morpholin-4-yl-ethyl)-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   Benzyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   2-(3-Phenyl-imidazo[1,2-a]pyrazin-8-ylamino)-ethanol, -   1-Butyl-3-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-urea, -   N-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-acetamide, -   N-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-acetamide, -   2,6-Dimethyl-4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   3-(4-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-ylamine, -   Cyclopropyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   [3-(4-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Methyl-[3-(2-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   Methyl-[3-(3-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   Methyl-[3-(2-phenoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   (3-Biphenyl-2-yl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine, -   [3-(2-Benzyloxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone, -   [3-(3-Isopropyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(4-tert-Butyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(4-Cyclohexyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(3,5-Bis-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-benzoic acid, -   3-(8-Methylamino-imidazo[1,2-a]pyrazin-4-yl)-benzoic acid, -   Methyl-(3-o-tolyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   [4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-carbamic acid     benzyl ester, -   Methyl-[3-(4-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   [3-(2,4-Difluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(3,4-Dichloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(3-Fluoro-4-methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   (3-Biphenyl-4-yl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine, -   (3-Biphenyl-3-yl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine, -   [3-(4-Benzyloxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Methyl-(3-naphthalen-1-yl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   [3-(2-Chloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   N-[3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]acetamide, -   Methyl-[3-(2-trifluoromethoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   Methyl-[3-(3-trifluoromethoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   Cyclopropyl-{3-[3-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine, -   3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   Methyl-[3-(4-trifluoromethoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   [3-(2-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(3,4-Difluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   (3-Benzo[1,3]dioxol-5-yl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine, -   [3-(3-Chloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(4-Methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(2-Methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Methyl-[3-(4-phenoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   [3-(4-Benzyloxy-3-fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(4-Isopropyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   [3-(3,5-Bis-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, -   Cyclopropyl-[3-(3,4-dichloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-benzoic acid, -   Methyl-{3-[4-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine, -   Cyclopropyl-{3-[4-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine, -   Cyclopropyl-[3-(4-dimethylamino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   Cyclopropyl-[3-(4-phenoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone, -   [4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-carbamic     acid benzyl ester, -   N-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-acetamide, -   [3-(3-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, -   [3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Methyl-(3-naphthalen-2-yl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-benzoic acid, -   [3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, -   Methyl-{3-[3-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine, -   [3-(3-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)—N-(2-morpholin-4-yl-ethyl)-benzamide, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)—N-(3-morpholin-4-yl-propyl)-benzamide, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)—N-(3-pyrrolidin-1-yl-propyl)-benzamide, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (S)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (S)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   (S)-3-Hydroxy-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[3-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, -   4-Pyrrolidin-1-yl-piperidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, -   4-Hydroxy-piperidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide -   (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[3-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   4-Hydroxy-piperidine-1-carboxylic     acid[3-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (R)-2-Dimethylaminomethyl-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea, -   (R)-3-Hydroxy-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, -   [5-(4-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Methyl-(5-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   Methyl-(5-thiophen-3-yl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-5-yl)-phenol, -   N-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-5-yl)-phenyl]-acetamide, -   [3,5-Bis-(4-fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   (3,5-Diphenyl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine, -   Methyl-(6-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-6-yl)-phenol, -   6-Phenyl-imidazo[1,2-a]pyrazin-8-ylamine and -   Dimethyl-(3-phenyl-imidazo[1,2-a]pyrazin-5-yl-amine.

Another preferred group of compounds of Formula (I) are compounds selected from the group consisting of:

-   Methyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   Ethyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   Cyclopropyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone, -   [4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-carbamic acid     benzyl ester, -   [3-(3-Fluoro-4-methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   Methyl-[3-(4-trifluoromethoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   [3-(4-Benzyloxy-3-fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Cyclopropyl-[3-(4-dimethylamino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone, -   [4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-carbamic     acid benzyl ester, -   [3-(3-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, -   [3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   Methyl-(3-naphthalen-2-yl-imidazo[1,2-a]pyrazin-8-yl)-amine, -   [3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, -   [3-(3-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine, -   3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (S)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (S)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   (S)-3-Hydroxy-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic     acid[3-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, -   4-Pyrrolidin-1-yl-piperidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, -   4-Hydroxy-piperidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, -   1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea, -   (R)-3-Hydroxy-pyrrolidine-1-carboxylic     acid[4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea     and -   1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, -   or a prodrug or pharmaceutically acceptable salt thereof.     Biological Activity

The PKs whose catalytic activity is modulated by the compounds of this invention include protein tyrosine kinases of which there are two types, receptor tyrosine kinases (RTKs) and cellular tyrosine kinases (CTKs), and serine-threonine kinases (STKs). RTK mediated signal transduction is initiated by extracellular interaction with a specific growth factor (ligand), followed by receptor dimerization, transient stimulation of the intrinsic protein tyrosine kinase activity and phosphorylation. Binding sites are thereby created for intracellular signal transduction molecules and lead to the formation of complexes with a spectrum of cytoplasmic signaling molecules that facilitate the appropriate cellular response (e.g., cell division, metabolic effects on the extracellular microenvironment, etc.). See, Schlessinger and Ullrich, 1992, Neuron 9:303–391.

It has been shown that tyrosine phosphorylation sites on growth factor receptors function as high-affinity binding sites for SH2 (src homology) domains of signaling molecules. Fantl et al., 1992, Cell 69:413–423, Songyang et al., 1994, Mol. Cell. Biol. 14:2777–2785), Songyang et al., 1993, Cell 72:767–778, and Koch et al., 1991, Science 252:668–678. Several intracellular substrate proteins that associate with RTKs have been identified. They may be divided into two principal groups: (1) substrates that have a catalytic domain, and (2) substrates which lack such domain but which serve as adapters and associate with catalytically active molecules. Songyang et al., 1993, Cell 72:767–778. The specificity of the interactions between receptors and SH2 domains of their substrates is determined by the amino acid residues immediately surrounding the phosphorylated tyrosine residue. Differences in the binding affinities between SH2 domains and the amino acid sequences surrounding the phosphotyrosine residues on particular receptors are consistent with the observed differences in their substrate phosphorylation profiles. Songyang et al., 1993, Cell 72:767–778. These observations suggest that the function of each RTK is determined not only by its pattern of expression and ligand availability but also by the array of downstream signal transduction pathways that are activated by a particular receptor. Thus, phosphorylation provides an important regulatory step which determines the selectivity of signaling pathways recruited by specific growth factor receptors, as well as differentiation factor receptors.

STKs, being primarily cytosolic, affect the internal biochemistry of the cell, often as a down-line response to a PTK event. STKs have been implicated in the signaling process which initiates DNA synthesis and subsequent mitosis leading to cell proliferation.

Thus, PK signal transduction results in, among other responses, cell proliferation, differentiation, growth and metabolism. Abnormal cell proliferation may result in a wide array of disorders and diseases, including the development of neoplasia such as carcinoma, sarcoma, glioblastoma and hemangioma, disorders such as leukemia, psoriasis, arteriosclerosis, arthritis and diabetic retinopathy and other disorders related to uncontrolled angiogenesis and/or vasculogenesis.

A precise understanding of the mechanism by which the compounds of this invention inhibit PKs is not required in order to practice the present invention. However, while not hereby being bound to any particular mechanism or theory, it is believed that the compounds interact with the amino acids in the catalytic region of PKs. PKs typically possess a bi-lobate structure wherein ATP appears to bind in the cleft between the two lobes in a region where the amino acids are conserved among PKs. Inhibitors of PKs are believed to bind by non-covalent interactions such as hydrogen bonding, van der Waals forces and ionic interactions in the same general region where the aforesaid ATP binds to the PKs. Specificity of a particular molecule for a particular PK may then arise as the result of additional interactions between the various substituents on the aryl-substituted imidazopyrazine core and the amino acid domains specific to particular PKs. Thus, different imidazopyrazine substituents may contribute to preferential binding to particular PKs. The ability to select compounds active at different ATP (or other nucleotide) binding sites makes the compounds of this invention useful for targeting any protein with such a site. The compounds disclosed herein thus have utility in in vitro assays for such proteins as well as exhibiting in vivo therapeutic effects through interaction with such proteins.

Additionally, the compounds of the present invention provide a therapeutic approach to the treatment of many kinds of solid tumors, including but not limited to carcinomas, sarcomas including Kaposi's sarcoma, erythroblastoma, glioblastoma, meningioma, astrocytoma, melanoma and myoblastoma. Treatment or prevention of non-solid tumor cancers such as leukemia are also contemplated by this invention. Indications may include, but are not limited to brain cancers, bladder cancers, ovarian cancers, gastric cancers, pancreas cancers, colon cancers, blood cancers, lung cancers and bone cancers.

Further examples, without limitation, of the types of disorders related to inappropriate PK activity that the compounds described herein may be useful in preventing, treating and studying, are cell proliferative disorders, fibrotic disorders and metabolic disorders.

Cell proliferative disorders, which may be prevented, treated or further studied by the present invention include cancer, blood vessel proliferative disorders and mesangial cell proliferative disorders.

Blood vessel proliferative disorders refer to disorders related to abnormal vasculogenesis (blood vessel formation) and angiogenesis (spreading of blood vessels). While vasculogenesis and angiogenesis play important roles in a variety of normal physiological processes such as embryonic development, corpus luteum formation, wound healing and organ regeneration, they also play a pivotal role in cancer development where they result in the formation of new capillaries needed to keep a tumor alive. Other examples of blood vessel proliferation disorders include arthritis, where new capillary blood vessels invade the joint and destroy cartilage, and ocular diseases, like diabetic retinopathy, where new capillaries in the retina invade the vitreous, bleed and cause blindness.

Two structurally related RTKs have been identified to bind VEGF with high affinity: the fms-like tyrosine 1 (flt-1) receptor (Shibuya et al., 1990, Oncogene, 5:519–524; De Vries et al., 1992, Science, 255:989–991) and the KDR/FLK-1 receptor, also known as VEGF-R2. Vascular endothelial growth factor (VEGF) has been reported to be an endothelial cell specific mitogen with in vitro endothelial cell growth promoting activity. Ferrara & Henzel, 1989, Biochein. Biophys. Res. Comm., 161:851–858; Vaisman et al., 1990, J. Biol. Chem., 265:19461–19566. Information set forth in U.S. Application Ser. Nos. 08/193,829, 08/038,596 and 07/975,750, strongly suggest that VEGF is not only responsible for endothelial cell proliferation, but also is the prime regulator of normal and pathological angiogenesis. See generally, Klagsburn & Soker, 1993, Current Biology, 3(10)699–702; Houck, et al., 1992, J. Biol. Chem., 267:26031–26037.

Normal vasculogenesis and angiogenesis play important roles in a variety of physiological processes such as embryonic development, wound healing, organ regeneration and female reproductive processes such as follicle development in the corpus luteum during ovulation and placental growth after pregnancy. Folkman & Shing, 1992, J. Biological Chem., 267(16):10931–34. Uncontrolled vasculogenesis and/or angiogenesis has been associated with diseases such as diabetes as well as with malignant solid tumors that rely on vascularization for growth. Klagsbum & Soker, 1993, Current Biology, 3(10):699–702; Folkham, 1991, J. Natl. Cancer Inst., 82:4–6; Weidner, et al., 1991, New Engl. J. Med., 324:1–5.

The surmised role of VEGF in endothelial cell proliferation and migration during angiogenesis and vasculogenesis indicates an important role for the KDR/FLK-1 receptor in these processes. Diseases such as diabetes mellitus (Folkman, 198, in XI ^(th) Congress of Thrombosis and Haemostasis (Verstraeta, et al., eds.), pp. 583–596, Leuven University Press, Leuven) and arthritis, as well as malignant tumor growth may result from uncontrolled angiogenesis. See e.g., Folkman, 1971, N. Engl. J. Med., 285:1182–1186. The receptors to which VEGF specifically binds are an important and powerful therapeutic target for the regulation and modulation of vasculogenesis and/or angiogenesis and a variety of severe diseases which involve abnormal cellular growth caused by such processes. Plowman, et al., 1994, DN&P, 7(6):334–339. More particularly, the KDR/FLK-1 receptor's highly specific role in neovascularization make it a choice target for therapeutic approaches to the treatment of cancer and other diseases which involve the uncontrolled formation of blood vessels.

Thus, the present invention provides compounds that regulate, modulate and/or inhibit vasculogenesis and/or angiogenesis by affecting the enzymatic activity of the KDR/FLK-1 receptor and interfering with the signal transduced by KDR/FLK-1. Thus the present invention provides a therapeutic approach to the treatment of many kinds of solid tumors including, but not limited to, glioblastoma, melanoma and Kaposi's sarcoma, and ovarian, lung, mammary, prostate, pancreatic, colon and epidermoid carcinoma. In addition, data suggests the administration of compounds which inhibit the KDR/Flk-1 mediated signal transduction pathway may also be used in the treatment of hemangioma, restenois and diabetic retinopathy.

Furthermore, this invention relates to the inhibition of vasculogenesis and angiogenesis by other receptor-mediated pathways, including the pathway comprising the flt-1 receptor.

Receptor tyrosine kinase mediated signal transduction is initiated by extracellular interaction with a specific growth factor (ligand), followed by receptor dimerization, transient stimulation of the intrinsic protein tyrosine kinase activity and autophosphorylation. Binding sites are thereby created for intracellular signal transduction molecules which leads to the formation of complexes with a spectrum of cytoplasmic signalling molecules that facilitate the appropriate cellular response, e.g., cell division and metabolic effects to the extracellular microenvironment. See, Schlessinger and Ullrich, 1992, Neuron, 9:1–20.

The close homology of the intracellular regions of KDR/FLK-1 with that of the PDGF-β receptor (50.3% homology) and/or the related flt-1 receptor indicates the induction of overlapping signal transduction pathways. For example, for the PDGF-β receptor, members of the src family (Twamley et al., 1993, Proc. Natl. Acad. Sci. USA, 90:7696–7700), phosphatidylinositol-3′-kinase (Hu et al., 1992, Mol. Cell. Biol., 12:981–990), phospholipase cγ (Kashishian & Cooper, 1993, Mol. Cell. Biol., 4:49–51), ras-GTPase-activating protein, (Kashishian et al., 1992, EMBO J., 11:1373–1382), PTP-ID/syp (Kazlauskas et al., 1993, Proc. Natl. Acad. Sci. USA, 10 90:6939–6943), Grb2 (Arvidsson et al., 1994, Mol. Cell. Biol., 14:6715–6726), and the adapter molecules Shc and Nck (Nishimura et al., 1993, Mol. Cell. Biol., 13:6889–6896), have been shown to bind to regions involving different autophosphorylation sites. See generally, Claesson-Welsh, 1994, Prog. Growth Factor Res., 5:37–54. Thus, it is likely that signal transduction pathways activated by KDR/FLK-1 include the ras pathway (Rozakis et al., 1992, Nature, 360:689–692), the PI-3′-kinase, the src-mediated and the plcγ-mediated pathways. Each of these pathways may play a critical role in the angiogenic and/or vasculogenic effect of KDR/FLK-1 in endothelial cells. Consequently, a still further aspect of this invention relates to the use of the organic compounds described herein to modulate angiogenesis and vasculogenesis as such processes are controlled by these pathways.

Conversely, disorders related to the shrinkage, contraction or closing of blood vessels, such as restenosis, are also implicated and may be treated or prevented by the methods of this invention.

Fibrotic disorders refer to the abnormal formation of extracellular matrices. Examples of fibrotic disorders include hepatic cirrhosis, mesangial cell proliferative disorders and pulmonary fibrosis. Hepatic cirrhosis is characterized by the increase in extriacellular matrix constituents resulting in the formation of a hepatic scar. An increased extracellular matrix resulting in a hepatic scar can also be caused by a viral infection such as hepatitis. Lipocytes appear to play a major role in hepatic cirrhosis. Other fibrotic disorders implicated include atherosclerosis. Pulmonary fibrosis may result from radiation treatment or treatment with chemotherapeutic drugs.

Mesangial cell proliferative disorders refer to disorders brought about by abnormal proliferation of mesangial cells. Mesangial proliferative disorders include various human renal diseases such as glomerulonephritis, diabetic nephropathy and malignant nephrosclerosis as well as such disorders as thrombotic microangiopathy syndromes, transplant rejection, and glomerulopathies. The RTK PDGFR has been implicated in the maintenance of mesangial cell proliferation. Floege et al., 1993, Kidney International 43:47S–54S.

Many cancers are cell proliferative disorders and, as noted previously, PKs have been associated with cell proliferative disorders. Thus, it is not surprising that PKs such as, for example, members of the RTK family have been associated with the development of cancer. Some of these receptors, like EGFR (Tuzi et al., 1991, Br. J. Cancer 63:227–233, Torp et al., 1992, APMIS 100:713–719) HER2/neu (Slamon et al., 1989, Science 244:707–712) and PDGF-R (Kumabe et al., 1992, Oncogene, 7:627–633) are over-expressed in many tumors and/or persistently activated by autocrine loops. In fact, in the most common and severe cancers these receptor over-expressions (Akbasak and Suner-Akbasak et al., 1992, J. Neurol. Sci., 111:119–133, Dickson et al., 1992, Cancer Treatment Res. 61:249–273, Korc et al., 1992, J. Clin. Invest. 90:1352–1360) and autocrine loops (Lee and Donoghue, 1992, J. Cell. Biol., 118:1057–1070, Korc et al., supra, Akbasak and Suner-Akbasak et al., supra) have been demonstrated. For example, EGFR has been associated with squamous cell carcinoma, astrocytoma, glioblastoma, head and neck cancer, lung cancer and bladder cancer. HER2 has been associated with breast, ovarian, gastric, lung, pancreas and bladder cancer. PDGFR has been associated with glioblastoma and melanoma as well as lung, ovarian and prostate cancer. The RTK c-met has also been associated with malignant tumor formation. For example, c-met has been associated with, among other cancers, colorectal, thyroid, pancreatic, gastric and hepatocellular carcinomas and lymphomas. Additionally c-met has been linked to leukemia. Over-expression of the c-met gene has also been detected in patients with Hodgkins disease and Burkitts disease.

IGF-IR, in addition to being implicated in nutritional support and in type-II diabetes, has also been associated with several types of cancers. For example, IGF-I has been implicated as an autocrine growth stimulator for several tumor types,

e.g. human breast cancer carcinoma cells (Arteaga et al., 1989, J. Clin. Invest. 84:1418–1423) and small lung tumor cells (Macauley et al., 1990, Cancer Res., 50:2511–2517). In addition, IGF-I, while integrally involved in the normal growth and differentiation of the nervous system, also appears to be an autocrine stimulator of human gliomas. Sandberg-Nordqvist et al., 1993, Cancer Res. 53:2475–2478. The importance of IGF-IR and its ligands in cell proliferation is further supported by the fact that many cell types in culture (fibroblasts, epithelial cells, smooth muscle cells, T-lymphocytes, myeloid cells, chondrocytes and osteoblasts (the stem cells of the bone marrow)) are stimulated to grow by IGF-I. Goldring and Goldring, 1991, Eukaryotic Gene Expression, 1:301–326. Baserga and Coppola suggest that IGF-IR plays a central role in the mechanism of transformation and, as such, could be a preferred target for therapeutic interventions for a broad spectrum of human malignancies. Baserga, 1995, Cancer Res., 55:249–252, Baserga, 1994, Cell 79:927–930, Coppola et al., 1994, Mol. Cell. Biol., 14:4588–4595.

STKs have been implicated in many types of cancer including, notably, breast cancer (Cance, et al., Int. J. Cancer, 54:571–77 (1993)).

The association between abnormal PK activity and disease is not restricted to cancer. For example, RTKs have been associated with diseases such as psoriasis, diabetes mellitus, endometriosis, angiogenesis, atheromatous plaque development, Alzheimer's disease, restenosis, von Hippel-Lindau disease, epidermal hyperproliferation, neurodegenerative diseases, age-related macular degeneration and hemangiomas. For example, EGFR has been indicated in corneal and dermal wound healing. Defects in Insulin-R and IGF-1R are indicated in type-II diabetes mellitus. A more complete correlation between specific RTKs and their therapeutic indications is set forth in Plowman et al., 1994, DN&P 7:334–339.

As noted previously, not only RTKs but CTKs including, but not limited to, src, abl, fps, yes, fyn, lyn, lck, blk, hck, fgr and yrk (reviewed by Bolen et al., 1992, FASEB J., 6:3403–3409) are involved in the proliferative and metabolic signal transduction pathway and thus could be expected, and have been shown, to be involved in many PTK-mediated disorders to which the present invention is directed. For example, mutated src (v-src) has been shown to be an oncoprotein (pp60^(v-src)) in chicken. Moreover, its cellular homolog, the proto-oncogene pp60^(c-src) transmits oncogenic signals of many receptors. Over-expression of EGFR or HER2/neu in tumors leads to the constitutive activation of pp60^(c-src), which is characteristic of malignant cells but absent in normal cells. On the other hand, mice deficient in the expression of c-src exhibit an osteopetrotic phenotype, indicating a key participation of c-src in osteoclast function and a possible involvement in related disorders.

Similarly, Zap70 has been implicated in T-cell signaling which may relate to autoimmune disorders.

STKs have been associated with inflammation, autoimmune disease, immunoresponses, and hyperproliferation disorders such as restenosis, fibrosis, psoriasis, osteoarthritis and rheumatoid arthritis.

PKs have also been implicated in embryo implantation. Thus, the compounds of this invention may provide an effective method of preventing such embryo implantation and thereby be useful as birth control agents. Additional disorders which may be treated or prevented using the compounds of this invention are immunological disorders such as autoimmune disease, AIDS and cardiovasular disorders such as atherosclerosis.

Finally, both RTKs and CTKs are currently suspected as being involved in hyperimmune disorders.

The compounds and data presented are not to be construed as limiting the scope of this invention in any manner whatsoever.

Administration and Pharmaceutical Composition

A compound of the present invention or a pharmaceutically acceptable salt thereof, can be administered as such to a human patient or can be administered in pharmaceutical compositions in which the foregoing materials are mixed with suitable carriers or excipient(s). Techniques for formulation and administration of drugs may be found in “Remington's Pharmacological Sciences,” Mack Publishing Co., Easton, Pa., latest edition.

As used herein, “administer” or “administration” refers to the delivery of a compound of Formula (I) or a pharmaceutically acceptable salt thereof or of a pharmaceutical composition containing a compound of Formula (I) or a pharmaceutically acceptable salt thereof of this invention to an organism for the purpose of prevention or treatment of a PK-related disorder.

Suitable routes of administration may include, without limitation, oral, rectal, transmucosal or intestinal administration or intramuscular, subcutaneous, intramedullary, intrathecal, direct intraventricular, intravenous, intravitreal, intraperitoneal, intranasal, or intraocular injections. The preferred routes of administration are oral and parenteral.

Alternatively, one may administer the compound in a local rather than systemic manner, for example, via injection of the compound directly into a solid tumor, often in a depot or sustained release formulation.

Furthermore, one may administer the drug in a targeted drug delivery system, for example, in a liposome coated with tumor-specific antibody. The liposomes will be targeted to and taken up selectively by the tumor.

Pharmaceutical compositions of the present invention may be manufactured by processes well known in the art, e.g., by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping or lyophilizing processes.

Pharmaceutical compositions for use in accordance with the present invention may be formulated in conventional manner using one or more physiologically acceptable carriers comprising excipients and auxiliaries which facilitate processing of the active compounds into preparations which can be used pharmaceutically. Proper formulation is dependent upon the route of administration chosen.

For injection, the compounds of the invention may be formulated in aqueous solutions, preferably in physiologically compatible buffers such as Hanks' solution, Ringer's solution, or physiological saline buffer. For transmucosal administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are generally known in the art.

For oral administration, the compounds can be formulated by combining the active compounds with pharmaceutically acceptable carriers well known in the art. Such carriers enable the compounds of the invention to be formulated as tablets, pills, lozenges, dragees, capsules, liquids, gels, syrups, slurries, suspensions and the like, for oral ingestion by a patient. Pharmaceutical preparations for oral use can be made using a solid excipient, optionally grinding the resulting mixture, and processing the mixture of granules, after adding other suitable auxiliaries if desired, to obtain tablets or dragee cores. Useful excipients are, in particular, fillers such as sugars, including lactose, sucrose, mannitol, or sorbitol, cellulose preparations such as, for example, maize starch, wheat starch, rice starch and potato starch and other materials such as gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethyl-cellulose, sodium carboxymethylcellulose, and/or polyvinyl-pyrrolidone (PVP). If desired, disintegrating agents may be added, such as cross-linked polyvinyl pyrrolidone, agar, or alginic acid. A salt such as sodium alginate may also be used.

Dragee cores are provided with suitable coatings. For this purpose, concentrated sugar solutions may be used which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures. Dyestuffs or pigments may be added to the tablets or dragee coatings for identification or to characterize different combinations of active compound doses.

Pharmaceutical compositions which can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer, such as glycerol or sorbitol. The push-fit capsules can contain the active ingredients in admixture with a filler such as lactose, a binder such as starch, and/or a lubricant such as talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds may be dissolved or suspended in suitable liquids, such as fatty oils, liquid paraffin, or liquid polyethylene glycols. Stabilizers may be added in these formulations, also.

Pharmaceutical compositions which may also be used include hard gelatin capsules. As a non-limiting example, the active compound capsule oral drug product formulation may be as 50 and 200 mg dose strengths.

For administration by inhalation, the compounds for use according to the present invention are conveniently delivered in the form of an aerosol spray using a pressurized pack or a nebulizer and a suitable propellant, e.g., without limitation, dichlorodifluoromethane, trichlorofluoromethane, dichlorotetra-fluoroethane or carbon dioxide. In the case of a pressurized aerosol, the dosage unit may be controlled by providing a valve to deliver a metered amount. Capsules and cartridges of, for example, gelatin for use in an inhaler or insufflator may be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.

The compounds may also be formulated for parenteral administration,

e.g., by bolus injection or continuous infusion. Formulations for injection may be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulating materials such as suspending, stabilizing and/or dispersing agents.

Pharmaceutical compositions for parenteral administration include aqueous solutions of a water soluble form, such as, without limitation, a salt, of the active compound. Additionally, suspensions of the active compounds may be prepared in a lipophilic vehicle. Suitable lipophilic vehicles include fatty oils such as sesame oil, synthetic fatty acid esters such as ethyl oleate and triglycerides, or materials such as liposomes. Aqueous injection suspensions may contain substances which increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol, or dextran. Optionally, the suspension may also contain suitable stabilizers and/or agents that increase the solubility of the compounds to allow for the preparation of highly concentrated solutions.

Alternatively, the active ingredient may be in powder form for constitution with a suitable vehicle, e.g., sterile, pyrogen-free water, before use.

The compounds may also be formulated in rectal compositions such as suppositories or retention enemas, using, e.g., conventional suppository bases such as cocoa butter or other glycerides.

In addition to the fomulations described previously, the compounds may also be formulated as depot preparations. Such long acting formulations may be administered by implantation (for example, subcutaneously or intramuscularly) or by intramuscular injection. A compound of this invention may be formulated for this route of administration with suitable polymeric or hydrophobic materials (for instance, in an emulsion with a pharamcologically acceptable oil), with ion exchange resins, or as a sparingly soluble derivative such as, without limitation, a sparingly soluble salt.

Alternatively, other delivery systems for hydrophobic pharmaceutical compounds may be employed. Liposomes and emulsions are well known examples of delivery vehicles or carriers for hydrophobic drugs. In addition, certain organic solvents such as dimethylsulfoxide also may be employed, although often at the cost of greater toxicity.

Additionally, the compounds may be delivered using a sustained-release system, such as semipermeable matrices of solid hydrophobic polymers containing the therapeutic agent. Various sustained-release materials have been established and are well known by those skilled in the art. Sustained-release capsules may, depending on their chemical nature, release the compounds for a few weeks up to over 100 days. Depending on the chemical nature and the biological stability of the therapeutic reagent, additional strategies for protein stabilization may be employed.

The pharmaceutical compositions herein also may comprise suitable solid or gel phase carriers or excipients. Examples of such carriers or excipients include, but are not limited to, calcium carbonate, calcium phosphate, various sugars, starches, cellulose derivatives, gelatin, and polymers such as polyethylene glycols.

Many of the PK modulating compounds of the invention may be provided as physiologically acceptable salts wherein the claimed compound may form the negatively or the positively charged species. Examples of salts in which the compound forms the positively charged moiety include, without limitation, quaternary ammonium (defined elsewhere herein), salts such as the hydrochloride, sulfate, carbonate, lactate, tartrate, malate, maleate, succinate wherein the nitrogen atom of the quaternary ammonium group is a nitrogen of the selected compound of this invention which has reacted with the appropriate acid. Salts in which a compound of this invention forms the negatively charged species include, without limitation, the sodium, potassium, calcium and magnesium salts formed by the reaction of a carboxylic acid group in the compound with an appropriate base (e.g. sodium hydroxide (NaOH), potassium hydroxide (KOH), Calcium hydroxide (Ca(OH)₂), etc.).

Pharmaceutical compositions suitable for use in the present invention include compositions wherein the active ingredients are contained in an amount sufficient to achieve the intended purpose, e.g., the modulation of PK activity or the treatment or prevention of a PK-related disorder.

More specifically, a therapeutically effective amount means an amount of compound effective to prevent, alleviate or ameliorate symptoms of disease or prolong the survival of the subject being treated.

Determination of a therapeutically effective amount is well within the capability of those skilled in the art, especially in light of the detailed disclosure provided herein.

For any compound used in the methods of the invention, the therapeutically effective amount or dose can be estimated initially from cell culture assays. Then, the dosage can be formulated for use in animal models so as to achieve a circulating concentration range that includes the IC₅₀ as determined in cell culture (i.e., the concentration of the test compound which achieves a half-maximal inhibition of the PK activity). Such information can then be used to more accurately determine useful doses in humans.

Toxicity and therapeutic efficacy of the compounds described herein can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., by determining the IC₅₀ and the LD₅₀ (both of which are discussed elsewhere herein) for a subject compound. The data obtained from these cell culture assays and animal studies can be used in formulating a range of dosage for use in humans. The dosage may vary depending upon the dosage form employed and the route of administration utilized. The exact formulation, route of administration and dosage can be chosen by the individual physician in view of the patient's condition. (See e.g., Fingl, et al., 1975, in “The Pharmacological Basis of Therapeutics”, Ch. 1 p. 1).

Dosage amount and interval may be adjusted individually to provide plasma levels of the active species which are sufficient to maintain the kinase modulating effects. These plasma levels are referred to as minimal effective concentrations (MECs). The MEC will vary for each compound but can be estimated from in vitro data, e.g., the concentration necessary to achieve 50–90% inhibition of a kinase may be ascertained using the assays described herein. Dosages necessary to achieve the MEC will depend on individual characteristics and route of administration. HPLC assays or bioassays can be used to determine plasma concentrations.

Dosage intervals can also be determined using MEC value. Compounds should be administered using a regimen that maintains plasma levels above the MEC for 10–90% of the time, preferably between 30–90% and most preferably between 50–90%.

At present, the therapeutically effective amounts of compounds of Formula I may range from approximately 3 mg/m² to 1500 mg/m² per day; preferably about 3 mg/m²/day. Even more preferably 50 mg/qm qd till 400 mg/qd.

In cases of local administration or selective uptake, the effective local concentration of the drug may not be related to plasma concentration and other procedures known in the art may be employed to determine the correct dosage amount and interval.

The amount of a composition administered will, of course, be dependent on the subject being treated, the severity of the affliction, the manner of administration, the judgment of the prescribing physician, etc.

The compositions may, if desired, be presented in a pack or dispenser device, such as an FDA approved kit, which may contain one or more unit dosage forms containing the active ingredient. The pack may for example comprise metal or plastic foil, such as a blister pack. The pack or dispenser device may be accompanied by instructions for administration. The pack or dispenser may also be accompanied by a notice associated with the container in a form prescribed by a governmental agency regulating the manufacture, use or sale of pharmaceuticals, which notice is reflective of approval by the agency of the form of the compositions or of human or veterinary administration. Such notice, for example, may be of the labeling approved by the U.S. Food and Drug Administration for prescription drugs or of an approved product insert. Compositions comprising a compound of the invention formulated in a compatible pharmaceutical carrier may also be prepared, placed in an appropriate container, and labeled for treatment of an indicated condition. Suitable conditions indicated on the label may include treatment of a tumor, inhibition of angiogenesis, treatment of fibrosis, diabetes, and the like.

It is also an aspect of this invention that a compound described herein, or its salt or prodrug, might be combined with other chemotherapeutic agents for the treatment of the diseases and disorders discussed above. For instance, a compound, salt or prodrug of this invention might be combined with alkylating agents such as fluorouracil (5-FU) alone or in further combination with leukovorin; or other alkylating agents such as, without limitation, other pyrimidine analogs such as UFT, capecitabine, gemcitabine and cytarabine, the alkyl sulfonates, e.g., busulfan (used in the treatment of chronic granulocytic leukemia), improsulfan and piposulfan; aziridines, e.g., benzodepa, carboquone, meturedepa and uredepa; ethyleneimines and methylmelamines, e.g., altretamine, triethylenemelamine, triethylenephosphoramide, triethylenethiophosphoramide and trimethylolmelamine; and the nitrogen mustards, e.g., chlorambucil (used in the treatment of chronic lymphocytic leukemia, primary macroglobulinemia and non-Hodgkin's lymphoma), cyclophosphamide (used in the treatment of Hodgkin's disease, multiple myeloma, neuroblastoma, breast cancer, ovarian cancer, lung cancer, Wilm's tumor and rhabdomyosarcoma), estramustine, ifosfamide, novembrichin, prednimustine and uracil mustard (used in the treatment of primary thrombocytosis, non-Hodgkin's lymphoma, Hodgkin's disease and ovarian cancer); triazines, e.g., dacarbazine (used in the treatment of soft tissue sarcoma); and topoisomerase inhibitors, e.g., irinotecan hydrochloride.

A compound, salt or prodrug of this invention can also be used in combination with other antimetabolite chemotherapeutic agents such as, without limitation, folic acid analogs, e.g. methotrexate (used in the treatment of acute lymphocytic leukemia, choriocarcinoma, mycosis fuingiodes breast cancer, head and neck cancer and osteogenic sarcoma) and pteropterin; and the purine analogs such as mercaptopurine and thioguanine which find use in the treatment of acute granulocytic, acute lymphocytic and chronic granulocytic leukemias.

It is contemplated that a compound, salt or prodrug of this invention can also be used in combination with natural product based chemotherapeutic agents such as, without limitation, the vinca alkaloids, e.g., vinblastin (used in the treatment of breast and testicular cancer), vincristine and vindesine; the epipodophylotoxins, e.g., etoposide and teniposide, both of which are useful in the treatment of testicular cancer and Kaposi's sarcoma; the antibiotic chemotherapeutic agents, e.g., daunorubicin, doxorubicin, epirubicin, mitomycin (used to treat stomach, cervix, colon, breast, bladder and pancreatic cancer), dactinomycin, temozolomide, plicamycin, bleomycin (used in the treatment of skin, esophagus and genitourinary tract cancer); and the enzymatic chemotherapeutic agents such as L-asparaginase.

In addition to the above, a compound, salt or prodrug of this invention could also be used in combination with the platinum coordination complexes (cisplatin, etc.); substituted ureas such as hydroxyurea; methylhydrazine derivatives, e.g., procarbazine; adrenocortical suppressants, e.g., mitotane, aminoglutethimide; and hormone and hormone antagonists such as the adrenocorticosteriods (e.g., prednisone), progestins (e.g., hydroxyprogesterone caproate); estrogens (e.g., diethylstilbesterol); antiestrogens such as tamoxifen; androgens, e.g., testosterone propionate; and aromatase inhibitors such as anastrozole.

Finally, it is also contemplated that the combination of a compound of this invention will be effective in combination with mitoxantrone, paclitaxel, cyclooxygenase-2 inhibitors known in the art, in particular Celebrex®, Paracoxib®, Vioxx®, Abbott's Cox-189 disclosed in PCT Publication No. WO 99/11605, topoisomerase inhibitors such as Camptosar®, Her-2 receptor antagonist such as Herceptin®, endostatin, Gleevac®, ImClone VEGF receptor antagonist IMC C225® for the treatment of solid tumor cancers or leukemias such as, without limitation, acute myelogenous (non-lymphocytic) leukemia.

EXAMPLES

General Procedure for Preparation of the Compounds of Examples 1–9

Synthesis of Imidazo[1,2-a]pyrazine—Intermediate C

To a solution of aminopyrazine (5 g, 53 mol, 1 eq.) in ethanol (212 ml) was added bromoacetaldehyde diethylacetal (12 ml, 80 mol, 1.5 eq.) and HBr (48%, 26.5 ml). The mixture was heated at 70–80° C. for 17 hours. The mixture was then cooled to rt (room temperature), then a mixture of 1N NaOH (200 ml) and 20% IPA/DCM (isopropyl alcohol/Dichloromethane) was added to the reaction mixture. The combined organic layer was dried over sodium sulfate and concentrated to afford 5.9 g of brown solid of imidazo[1,2-a]pyrazine (yield 94%).

¹HNMR (400 MHz, DMSO-d₆) δ 9.05 (m, 1H), 8.60 (dd, 1H), 8.13 (d, 1H), 7.87 (d, 1H), 7.81 (d, 1H).

MS m/z 120 [M⁺+1].

Synthesis of 3,5-Dibromo-imidazo[1,2-a]pyrazine—Intermediate D

To a solution of imidazo[1,2-a]pyrazine (intermediate C) (2.8 g, 23.5 mmol) in AcOH (acetic acid) (200 ml) was added bromine (6 ml, 5 eq.) via addition funnel, with the reaction flask protected from light. After addition, the flask was sealed. The mixture was stirred at rt for 24 hr., 6 ml (5 eq.) of additional Br₂ was added to the reaction mixture, which was further stirred at rt for 48 hr. The mixture was evaporated to remove Br₂ and acetic acid, and the residue was dissolved in 10% IPA/DCM, washed with sat. Na₂CO₃ (300 ml). The organics were combined, dried and concentrated to afford 5.9 g (yield 97%) of 3,5-dibromo-imidazo[1,2-a]pyrazine.

¹HNMR (400 MHz, DMSO-d₆) δ 9.05 (s, 1H), 8.09 (s, 1H), 7.99 (s, 1H).

MS m/z 278 [M⁺+1].

Example 1 (3-Bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine

3,5-Dibromo-imidazo[1,2-a]pyrazine (D) (2.0 g, 7 mol) was added to 2M methylamine in THF (tetrahydrofuran) (100 ml, 30 eq.). The mixture was heated at 70° C. in sealed tube for 3hr. The mixture was then cooled to rt, diluted with DCM (200 ml) and water (100 ml). The organic layer was washed with brine, dried and concentrated. The residue was purified on a silica gel column to give (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (yield 50%).

¹HNMR (400 MHz, DMSO-d₆) δ 7.64 (s, 1H), 7.53 (d, 1H), 7.42 (d, 1H), 2.94 (d, 3H).

MS m/z 228 [M⁺+1].

Example 2 3-Bromo-imidazo[1,2-a]pyrazin-8-ylamine

To a solution of 3,5-dibromo-imidazo[1,2-a]pyrazine (D) (500 mg, 1.8 mmol) in THF (4 ml) was added NH₄OH (4 ml). The mixture was heated at 50° C. in sealed tube overnight. Additional NH₄OH (4 ml) was added to the reaction mixture and was heated at 50° C. in sealed tube overnight. The mixture was then cooled to rt, diluted with DCM (200 ml) and IN HCl (50 ml). The organic layer was washed with 10N NaOH, brine, dried and concentrated. The residue was purified on a silica gel column to afford 190 mg (yield 50%) of 3-bromo-imidazo[1,2-a]pyrazin-8-ylamine.

¹HNMR (400 MHz, DMSO-d₆) δ 7.64 (s, 1H), 7.55 (d, 1H), 7.33 (d, 1H), 7.06 (br s, 2H).

MS m/z 214 [M⁺+1].

Example 3 (3-Bromo-imidazo[1,2-a]pyrazin-8-yl)-ethyl-amine

3,5-Dibromo-imidazo[1,2-a]pyrazine (D) (200 mg, 0.722 mol) was added to 2M ethylamine in THF (10.8 ml, 30 eq.). The mixture was heated at 70° C. in sealed tube for 8 hr. The mixture was then cooled to rt, and diluted with DCM (100 ml) and water (50 ml). The organic layer was washed with brine, dried and concentrated. The residue was purified on a silica gel column to give 92.2 mg (yield 53%) of (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-ethyl-amine as a crystalline solid.

¹HNMR (400 MHz, DMSO-d₆) δ 7.62 (s, 1H), 7.50 (d, 1H), 7.38 (d, 1H), 3.45 (q, 2H), 1.15 (t, 3H).

MS m/z 242 [M⁺+1].

Example 4 (3-Bromo-imidazo[1,2-a]pyrazin-8-yl)-butyl-amine

To a solution of 3,5-dibromo-imidazo[1,2-a]pyrazine (D) (200 mg, 0.72 mmol) in THF (3.6 ml) was added butylamine (2.2 ml, 21.6 mmol). The mixture was heated at 70° C. for 3 hr. The mixture was then cooled to rt, and diluted with DCM. The organic layer was washed with water, brine, dried and concentrated. The residue was purified on a silica gel column to afford 99 mg (yield 51%) of (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-butyl-amine.

¹HNMR (400 MHz, DMSO-d₆) δ 7.64 (s, 1H), 7.55 (d, 1H), 7.40 (d, 1H), 3.40 (q, 2H), 1.58 (t, 3H), 1.30 (t, 3H), 0.94 (t, 3H).

MS m/z 269 [M+].

Example 5 (3-Bromo-imidazo[1,2-a]pyrazin-8-yl)-isopropyl-amine

To a solution of 3,5-dibromo-imidazo[1,2-a]pyrazine (D) (200 mg, 0.72 mmol) in THF (3.6 ml) was added isopropylamine (1.3 ml, 14.4 mmol). The mixture was heated at 70° C. overnight. The mixture was then cooled to rt, diluted with DCM. The organic layer was washed with water, brine, dried and concentrated. The residue was purified on a silica gel column to afford 125 mg (yield 68%) of the title compound.

¹HNMR (400 MHz, DMSO-d₆) δ 7.64 (s, 1H), 7.52 (d, 1H), 7.41 (d, 1H), 7.30 (d, 1H), 4.34 (m, 1H), 1.22 (d, 6H).

MS m/z 255 [M+].

Example 6 (3-Bromo-imidazo[1,2-a]pyrazin-8-yl)-cyclopropyl-amine

To a solution of 3,5-dibromo-imidazo[1,2-a]pyrazine (D) (250 mg, 0.9 mmol) in THF (9 ml) was added cyclopropylamine (1.9 ml, 27 mmol) and diisopropylethylamine (DIPEA) (0.782 ml, 4.5 mmol). The mixture was heated at 50° C. in sealed tube overnight. The mixture was then cooled to rt, diluted with DCM and water. The organic layer was washed with brine, dried and concentrated. The residue was purified on a silica gel column to give 33 mg (yield 14.5%) of the title compound.

¹HNMR (400 MHz, DMSO-d₆) δ 7.78 (d, 1H), 7.64 (s, 1H), 7.59 (d, 1H), 7.46 (d, 1H), 2.90 (m, 1H), 0.71 (t, 3H), 0.65 (t, 2H).

MS m/z 254 [M⁺+1].

Example 7 Benzyl-(3-bromo-imidazo[1,2-a]pyrazin-8-yl)-amine

To a solution of 3,5-dibromo-imidazo[1,2-a]pyrazine (D) (200 mg, 0.72 mmol) in THF (9 ml) was added benzylamine (0.393 ml, 3.6 mmol) and diisopropylethylamine (DIPEA) (0.627 ml, 3.6 mmol). The mixture was heated at 70° C. for 3 days. The mixture was then cooled to rt, diluted with DCM and water. The organic layer was washed with brine, dried and concentrated. The residue was purified on a silica gel column to give 30 mg of the title compound.

Example 8 (3-Bromo-imidazo[1,2-a]pyrazin-8-yl)-(2-morpholin-4-yl-ethyl)-amine

To a solution of 3,5-dibromo-imidazo[1,2-a]pyrazine (D) (200 mg, 0.72 mmol) in methanol (3.6 ml) was added (2-morpholin-4-yl-ethyl)-amine (2.5 eq.) and diisopropylethylamine (DIPEA) (0.383 ml, 4.5 mmol). The mixture was heated at 70° C. overnight. The mixture was then cooled to rt, diluted with DCM and water. The organic layer was washed with brine, dried and concentrated. The residue was purified on a silica gel column to give 34 mg (yield 14%) of the title compound.

¹HNMR (400 MHz, DMSO-d₆) δ 7.61 (s, 1H), 7.53 (s, 1H), 7.52 (d, 1H), 7.45 (d, 1H), 3.70 (t, 4H), 3.64 (t, 4H), 3.38 (m, 2H), 2.68 (t, 2H).

MS m/z 326 [M⁺].

Example 9 2-(3-Bromo-imidazo[1,2-a]pyrazin-8-ylamino)-ethanol

To a solution of 3,5-dibromo-imidazo[1,2-a]pyrazine (D) (400 mg, 1.44 mmol) in dioxane (2 ml) was added ethanolamine (0.436 ml, 7.22 mmol). The mixture was heated at 80° C. in sealed tube for 5 hr. The mixture was then cooled to rt, diluted with 20% IPA/DCM and water. The organic layer was washed with brine, dried and concentrated. The residue was purified on a silica gel column to give 124 mg (yield 33%) of the title compound.

¹HNMR (400 MHz, DMSO-d₆) δ 7.62 (s, 1H), 7.52 (d, 1H), 7.40 (m, 1H), 7.38 (d, 1H), 4.56 (br s, 1H), 3.58 (t, 2H), 3.50 (t, 2H).

MS m/z 258 [M⁺+1].

(1) General procedures of Suzuki coupling reaction for preparing final products:

Method 1:

To a solution of (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-aryl or alkyl-amine (1 eq.) in THF (22 ml) was added boronic acid or ester (1.5 eq.), K₂CO₃, PdCl₂.Dppf.CH₂Cl₂ (0.1 eq). The mixture was heated at 70° C. in sealed tube overnight. The mixture was then cooled to rt, and diluted with 20% IPA/DCM and 1N NaOH. The organic layer was washed with brine, dried and concentrated. The residue was purified on a silica gel column to give the desired compounds.

(a) Method 2

(3-bromo-imidazo[1,2-a]pyrazin-8-yl)-aryl or alkyl-amine (1.0 eq.), boronic acid (1.5 eq), and 10% mmol Palladium tetrakistriphenylphosphine were weighted out and combined in a 5 ml microwave tube equipt for stirring. THF (2 ml) was then added followed by 1 ml of 1 N K₂CO₃. The bi-phasic orange/yellow solution was then sealed and heated in a microwave reactor at 160° C. for 10 minutes. The reaction mixture was then monitored by TLC (50/50 Ethyl Acetate/Hexanes) for consumption of the starting material. The crude mixture was then acidified with 10 ml of 2 N HCl solution and extracted twice with 50 ml of ether and water. The aqueous layers were then combined and pH rose above 10 with 2 N NaOH and extracted twice with 75 mL of dichloromethane. The organic layers were then combined and solvent removed under vacuum to provide a brown or yellow residue. This residue was then dissolved in a minimum of dichloromethane and purified by semi-prep HPLC (70% A/30% B for 10 minutes, then 5% A/95% B; Flow rate: 25 mL/min; A=Hexanes with 0.5% v/v MeOH; B=Ethyl Acetate 0.5% v/v MeOH).

Example 10 Methyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using Method 1, the title compound was prepared from (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (Example 1) and phenylboronic acid (from Aldrich) in 63% yield.

¹HNMR (400 MHz, DMSO-d₆) δ 7.71 (d, 1H), 7.69 (s, 1H), 7.65 (m, 2H), 7.55 (m, 3H), 7.45 (m, 1H), 7.33 (d, 1H), 3.0 (d, 3H).

MS m/z 225 [M⁺+1].

Example 11 3-Phenyl-imidazo[1,2-a]pyrazin-8-ylamine

Using the same procedure for preparing Example 10, the title compound was obtained in 66% yield from 3-bromo-imidazo[1,2-a]pyrazin-8-ylamine (Example 2), and benzene boronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 7.72 (d, 1H), 7.68 (s, 1H), 7.62 (d, 2H), 7.52 (m, 2H), 7.42 (m, 1H), 7.23 (d, 1H), 6.93 (br s, 2H).

MS m/z 211 [M⁺+1].

Example 12 3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-ylamine

Using the same procedure for preparing Example 10, the title compound was obtained in 66% yield from 3-bromo-imidazo[1,2-a]pyrazin-8-ylamine (Example 2) and 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenylamine (from Aldrich) as off-white solid.

¹HNMR (400 MHz, DMSO-d₆) δ 7.61 (d, 1H), 7.47 (s, 1H), 7.24 (m, 2H), 7.18 (d, 1H), 6.85 (br s, 2H), 6.68 (m, 2H), 5.42 (br s, 2H).

MS m/z 226 [M⁺+1].

Example 13 N-[4-(4-trifluoromethyl-benzamide-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-4-trifluoromethyl-benzamide

To a solution of 3-(4-amino-phenyl)-imidazo[1,2-a]pyrazin-8-ylamine (Example 12) (25 mg, 1 eq.) in DCM (1 ml) and DMF (0.7 ml) was added 4-(trifluoromethyl) benzoyl chloride (0.117 mmol, 1.05 eq) and triethylamine (0.031 ml, 2 eq.) at 0° C. The mixture was then stirred at room temperature overnight. The mixture was diluted with 20% IPA/DCM and water. The organic layer was washed with brine, dried and concentrated. The residue was purified on a silica gel column to give 11 mg (yield 17%) of the title compound.

¹HNMR (400 MHz, DMSO-d₆) δ 11.22 (s, 1H), 10.69 (s, 1H), 8.52 (m, 1H), 8.19 (m, 4H), 7.98 (m, 7H), 7.76 (m, 3H).

MS m/z 570 [M⁺+1].

Example 14 N-[4-(8-Amino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-4-trifluoromethyl-benzamide

A 51% yield of the title compound was obtained from the same reaction for preparing Example 13.

¹HNMR (400 MHz, DMSO-d₆) δ 10.65 (s, 1H), 8.16 (d, 2H), 7.95 (m, 4H), 7.77 (d, 1H), 7.68 (m, 3H), 7.26 (d, 1H), 7.00 (br s, 2H).

MS m/z 398 [M⁺+1].

Example 15 (3-Bromo-imidazo[1,2-a]pyrazin-8-yl)-(4-methoxy-phenyl)-amine

3,5-Dibromo-imidazo[1,2-a]pyrazine (intermediate D) (200 mg, 0.7 mmol) was added to a mixture of anisidine (445 mg, 5 eq.), trifluoroethanol (3.6 ml), DIPEA (diisopropylethylamine) (0.629 ml, 5 eq). The mixture was heated at 75–85° C. in sealed tube for 12 hr. The mixture was then cooled to room temperature, diluted with DCM and water. The organic layer was washed with 1N HCl, brine, dried and concentrated. The residue was purified on a silica gel column to give 56.6 mg (yield 50%) of the title compound as faint orange solid.

¹HNMR (400 MHz, DMSO-d₆) δ 9.55 (s, 1H), 7.87 (m, 2H), 7.76 (s, 1H), 7.72 (d, 1H), 7.49 (d, 1H), 6.89 (m, 2H), 3.72 (s, 3H).

MS m/z 319 [M+].

Example 16 (4-Methoxy-phenyl)-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using the same procedure for preparing Example 10, the title compound was obtained in 54% yield from (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-(4-methoxy-phenyl)-amine (Example 15) and benzene boronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 9.47 (s, 1H), 7.91 (m, 3H), 7.81 (s, 1H), 7.68 (m, 2H), 7.56 (m, 2H), 7.44 (m, 1H), 7.40 (d, 1H), 6.91 (m, 2H), 3.73 (s, 3H).

MS m/z 317 [M⁺+1].

Example 17 4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol

Using the same procedure for preparing Example 10, the title compound was obtained in 41% yield from (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (Example 1) and 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenol (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 9.75 (s, 1H), 7.59 (d, 1H), 7.52 (s, 1H), 7.45 (m, 1H), 7.41 (m, 2H), 7.27 (d, 1H), 6.90 (m, 2H), 2.93 (d, 3H).

MS m/z 241 [M⁺+1].

Example 18 Dimethyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine

Into a 150 ml sealed tube was placed 200 mg (0.722 mmol, 1 eq) of 3,5-dibromo-imidazo[1,2-a]pyrazine (intermediate D), 10.8 ml (21.67 mmol, 30 eq) of a 2 M solution of dimethylamine in THF, and 5 ml of MeOH. The mixture was heated at 75° C. for 8 h. According to thin-layer chromatography, some starting material was still present, along with two new products. To the sealed tube was added 5.4 ml of the dimethylamine solution, and the mixture was further heated at 75° C. overnight. TLC then showed no starting material remaining. The solvent was removed by vacuum, and the residue was partitioned between 50 ml H₂O and 100 ml 20% isopropanol in dichloromethane. The organic layer was washed with brine and dried with Na₂SO₄. After removal of solvent in vacuo, the residue was purified by silica gel flash chromatography using 85/15 hexane/EtOAc to elute the first product [(3-Bromo-imidazo[1,2-a]pyrazin-8-yl)-dimethyl-amine, 16.3 mg, 9% ], then 3% MeOH/CH₂Cl₂ to elute the second product [(3-bromo-imidazo[1,2-a]pyrazin-5-yl)-dimethyl-amine, 59.5 mg, 34%-starting material for Example 128].

[(3-Bromo-imidazo[1,2-a]pyrazin-8-yl)-dimethyl-amine: ¹H NMR (400 MHz, DMSO-d₆) δ 3.43 (s, 6H), 7.43 (d, J=3.2 Hz, 1H), 7.58 (d, J=3.2 Hz, 1H), 7.66 (s, 1H).

MS (EI) m/z 240, 242.

[(3-Bromo-imidazo[1,2-a]pyrazin-5-yl)-dimethyl-amine: ¹H NMR (400 MHz, DMSO-d₆) δ 2.77 (s, 6H), 7.59 (s, 1H), 7.81 (s, 1H), 8.74 (s, 1H).

MS (EI) m/z 240, 242.

Using the same procedure for preparing Example 10, the title compound was obtained in 67% yield from (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-dimethylamine and benzene boronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 7.40 (d, 1H), 7.71 (s, 1H), 7.62 (m, 1H), 7.61 (m, 1H), 7.54 (m, 2H), 7.46 (m, 1H), 7.34 (d, 1H), 3.48 (s, 6H).

MS m/z 239 [M⁺+1].

Example 19 Isopropyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using procedure for Example 10, the title compound was obtained in 31% yield from (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-isopropyl-amine (Example 5) and benzene boronic acid.

¹HMR (400 MHz, DMSO-d₆) δ 7.70 (m, 2H), 7.60 (d, 2H), 7.45 (m, 2H), 7.41 (m, 1H), 7.30 (d, 1H), 7.10 (d, 1H), 4.35 (m, 1H), 1.20 (s, 6H).

MS m/z 253 [M⁺+1].

Example 20 4-(8-Isopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol

Using the same procedure for preparing Example 10, the title compound was obtained in 23% yield from (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-isopropyl-amine (Example 5) and 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenol.

¹HNMR (400 MHz, DMSO-d₆) δ 10.0 (s, 1H), 7.90 (s, 1H), 7.75 (d, 1H), 7.45 (d, 2H), 7.21 (m, 1H), 7.00 (d, 2H), 4.35 (m, 1H), 1.30 (s, 6H).

MS m/z 269 [M⁺+1].

Example 21 Butyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using the same procedure for preparing Example 10, the title compound was obtained in 59% yield from (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-butyl-amine (Example 4) and benzene boronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 7.69 (m, 2H), 7.64 (m, 2H), 7.55 (m, 2H), 7.49 (m, 1H), 7.45 (m, 1H), 7.32 (d, 1H), 3.47 (m, 2H), 1.61 (m, 2H), 1.36 (m, 2H), 0.91 (t, 3H).

MS m/z 267 [M⁺+1].

Example 22 Ethyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using, the same procedure for preparing Example 10, the title compound was obtained (yield 76%) from (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-ethyl-amine (Example 3) and benzene boronic acid as off-white solid.

¹HNMR (400 MHz, DMSO-d₆) δ 7.68 (m, 2H), 7.62 (m, 2H), 7.54 (m, 3H), 7.44 (m, 1H), 7.30 (d, 1H), 3.49 (m, 2H), 1.18 (t, 3H).

MS m/z 239 [M⁺+1].

Example 23 (2-Morpholin-4-yl-ethyl)-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using the same procedure for preparing Example 10, the title compound was obtained in 66% yield from (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-(2-morpholin-4-yl-ethyl)-amine (Example 8) and benzene boronic acid as a brown oil.

¹H NMR (400 MHz, DMSO d-6) δ 2.43 (m, 4H), 2.56 (t, J=6.4 Hz, 2H), 3.58 (m, 6H), 7.31 (d, J=4.8 Hz, 1H), 7.46 (m, 1H), 7.54 (m, 3H), 7.63 (d, J=7.2 Hz, 2H), 7.69 (s, 1H), 7.70 (d, J=4.8 Hz, 1H).

MS m/z 324 [M⁺+1].

Example 24 Benzyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using the same procedure for preparing Example 10, the title compound was obtained from benzyl-(3-bromo-imidazo[1,2-a]pyrazin-8-yl)-amine (Example 7) and benzene boronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 7.61 (d, 1H), 7.55 (m, 5H), 7.42 (m, 4H), 7.345 (m, 2H), 7.30 (m, 1H), 6.38 (m, 1H), 4.82 (d, 2H).

MS m/z 301 [M⁺+1].

Example 25 2-(3-Phenyl-imidazo[1,2-a]pyrazin-8-ylamino)-ethanol

Using the same procedure for preparing Example 10, the title compound was obtained from 2-(3-bromo-imidazo[1,2-a]pyrazin-8-ylamino)-ethanol (Example 9) and benzene boronic acid.

MS m/z 255 [M⁺+1].

Example 26 1-Butyl-3-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-urea

To a mixture of 3-phenyl-imidazo[1,2-a]pyrazin-8-ylamine (Example 11) (28 mg, 0.133 mmol) in DCM (0.5 ml), DMF (1 ml) and THF (0.5 ml) was added butyl isocyanate (0.03 ml, 2 eq.). The mixture was heated at 60° C. for 8 hr. After cooling to rt, the mixture was diluted with EtOAc. The organic layer was washed with brine, dried and concentrated. The residue was purified on a silica gel column to give 15 mg (yield 36%) of the title compound.

¹HNMR (400 MHz, DMSO-d₆) δ 9.20 (s, 1H), 8.71 (br s, 1H), 8.13 (d, 1H), 7.90 (s, 1H), 7.68 (d, 2H), 7.57 (m, 2H), 7.52 (m, 2H), 3.26 (m, 2H), 1.51 (m, 2H), 1.3(m, 2H), 0.95 (t, 3H).

MS m/z 310 [M⁺+1].

Example 27 N-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-acetamide

Using Method 2, the title compound was obtained in 61% yield from Example 1 and 3-acetylamino-phenylboronic acid (from Lancaster).

¹HNMR (400 MHz, DMSO-d₆) δ 8.33 (s, 1H), 7.82 (s, 1H), 7.60 (m, 1H), 7.40 (t, 1H), 7.35 (d, 1H), 7.22 (t, 1H), 6.30 (m, br, 1H), 3.17 (d, 3H), 2.20 (s, 3H).

MS m/z 282 [M⁺+1].

Example 28 N-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-acetamide

Using Method 2, the title compound was prepared in 12% yield from 3-bromo-imidazo[1,2-a]pyrazin-8-yl)-cyclopropyl-amine (Example 6) and N-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenyl]-acetamide (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.70 (m, 2H), 7.56 (d, 1H), 7.43 (m, 5H), 6.27 (br s, 1H), 2.93 (m, 1H), 2.23 (s, 3H), 0.93 (m, 2H), 0.67 (m, 2H).

Example 29 2,6-Dimethyl-4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol

Using Method 2, the title compound was obtained from Example 1 and 2,6-dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 8.58 (br s, 1H), 7.63 (d, 1H), 7.51 (s, 1H), 7.44 (m, 1H), 7.29 (d, 1H), 7.16 (s, 2H), 2.96 (d, 3H), 2.36 (s, 6H).

MS m/z 269 [M⁺+1].

Example 30 3-(4-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-ylamine

Using the same procedure for preparing Example 10, the title compound was obtained from 3-bromo-imidazo[1,2-a]pyrazin-8-ylamine (Example 2) and 4-fluorobenzene boronic acid (From Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.68 (m, 4H), 7.34 (m, 2H), 7.24 (d, 1H), 6.94 (br s, 2H).

MS m/z 229 [M⁺+1].

Example 31 Cyclopropyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using the same procedure for preparing Example 10, the title compound was obtained from (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-cyclopropyl-amine (Example 6) and benzene boronic acid (From Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.76 (d, 1H), 7.69 (s, 1H), 7.65 (m, 2H), 7.63 (m, 1H), 7.55 (m, 2H), 7.45 (m, 1H), 7.36 (d, 1H), 2.95 (m, 1H), 0.73 (m, 2H), 0.65 (m, 2H).

MS m/z 251 [M⁺+1].

Example 32 [3-(4-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using the same procedure for preparing Example 10, the title compound was obtained from (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (Example 1) and 4-fluorobenzene boronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 7.56 (m, 4H), 7.34 (d, 1H), 7.16 (m, 2H), 3.16 (d, 3H).

Example 33 Methyl-[3-(2-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine

Using Method 2, the title compound was obtained in 37% yield from Example 1 and 2-(trifluoromethyl)phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.87 (d, 1H), 7.64 (m, 3H), 7.45 (s, 1H), 7.38 (d, 1H), 7.04 (d, 1H), 6.28 (br s, 1H), 3.20 (d, 3H).

MS m/z 293 [M⁺+1].

Example 34 Methyl-[3-(3-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine

Using Method 2, the title compound was obtained in 20% yield from Example 1 and 3-(trifluoromethyl)phenylboronic acid (from Fluka).

¹HNMR (400 MHz, DMSO-d₆) δ 8.68 (multiplets, 4H), 7.58 (s, 1H), 7.48 (d, 1H), 7.42 (d, 1H), 6.37 (br s, 1H), 3.16 (d, 3H).

MS m/z 293 [M⁺+1].

Example 35 Methyl-[3-(2-phenoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine

Using Method 2, the title compound was obtained in 38% yield from Example 1 and 2-phenoxy-phenylboronic acid (from Combi-Blocks).

¹HNMR (400 MHz, DMSO-d₆) δ 7.50 (m, 2H), 7.40 (m, 4H), 7.22 (m, 4H), 6.87 (d, 2H), 6.23 (br s, 1H), 3.09 (d, 3H).

MS m/z 317 [M⁺+1].

Example 36 (3-Biphenyl-2-yl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine

Using Method 2, the title compound was obtained in 50% yield from Example 1 and 2-phenyl-phenylboronic acid (from Lancaster).

¹HNMR (400 MHz, DMSO-d₆) δ 7.54 (m, 2H), 7.47 (m, 2H), 7.30 (s, 1H), 7.07 (m, 6H), 6.89 (d, 1H), 6.32 (br s, 1H), 3.08 (d, 3H).

MS m/z 301 [M⁺+1].

Example 37 [3-(2-Benzyloxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 31% yield from Example 1 and 2-phenyl-phenylboronic acid (from Combi-Blocks).

¹HNMR (400 MHz, DMSO-d₆) δ 7.56 (s, 1H), 7.39 (m, 2H), 7.24 (m, 7H), 7.06 (m, 2H), 6.26 (br s, 1H), 5.07 (s, 3H), 3.18 (d, 3H).

MS m/z 331 [M⁺+1].

Example 38 1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone

Using Method 2, the title compound was obtained in 39% yield from Example 1 and 4-acetyl-phenylboronic acid (from Aldrich).

¹H NMR (400 MHz, DMSO-d₆) δ 8.10 (m, 2H), 7.60 (m, 4H), 7.43 (d, 1H), 6.14 (br s, 1H), 3.16 (d, 3H), 2.63 (s, 3H).

MS m/z 267 [M⁺+1].

Example 39 1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone

Using Method 2, the title compound was obtained in 35% yield from Example 1 and 3-acetyl-phenylboronic acid (from Aldrich).

¹H NMR (400 MHz, DMSO-d₆) δ 8.13 (m, 1H), 8.00 (d, 1H), 7.73 (d, 1H), 7.59 (m, 2H), 7.52 (d, 1H), 7.37 (d, 1H), 6.27 (br s, 1H), 3.18 (d, 3H), 2.65 (s, 3H).

MS m/z 267 [M⁺+1].

Example 40 [3-(3-Isopropyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 26% yield from Example 1 and 3-isopropyl-phenylboronic acid (from Lancaster).

¹H NMR (400 MHz, DMSO-d₆) δ 7.54 (m, 2H), 7.33 (m, 5H), 6.23 (br s, 1H), 3.13 (m, 3H), 2.92 (m, 1H), 1.30 (d, 6H).

MS m/z 267 [M⁺+1].

Example 41 [3-(4-tert-Butyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 35% yield from Example 1 and 4-t-butyl-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.60 (m, 1H), 7.54 (m, 5H), 7.38 (d, 1H), 6.17 (br s, 1H), 3.20 (d, 3H), 1.37 (s, 9H).

MS m/z 281 [M⁺+1].

Example 42 [3-(4-Cyclohexyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 43% yield from Example 1 and 4-cyclohexyl-phenylboronic acid (from Lancaster).

¹HNMR (400 MHz, DMSO-d₆) δ 7.58 (m, 2H), 7.43 (m, 2H), 7.37 (m, 3H), 6.29 (br s, 1H), 3.14 (d, 3H), 2.55 (m, 1H), 1.87 (5H), 1.40 (m, 5H).

MS m/z 307 [M⁺+1].

Example 43 [3-(3,5-Bis-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 38% yield from Example 1 and 3,5-bis(trifluoromethyl)phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 8.00 (m, 2H), 7.90 (m, 1H), 7.67 (s, 1H), 7.47 (m, 2H), 6.20 (br s, 1H), 3.23 (d, 3H).

MS m/z 361 [M⁺+1].

Example 44 3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-benzoic acid

Using Method 2, the title compound was obtained in 33% yield from Example 1 and 3-carboxy-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 8.21 (s, 1H), 8.07 (d, 1H), 7.72 (d, 1H), 7.58 (3×m, 3H), 7.42 (d, 1H), 6.14 (s, br, 1H), 3.17 (d, 3H).

Example 45 3-(8-Methylamino-imidazo[1,2-a]pyrazin-4-yl)-benzoic acid

Using Method 2, the title compound was obtained in 15% yield from Example 1 and 4-carboxy-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 8.15 (m, 2H), 7.63 (m, 4H), 7.43 (d, 1H) 6.04 (s, br, 1H), 3.17 (d, 3H).

Example 46 Methyl-(3-o-tolyl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using Method 2, the title compound was obtained in 33% yield from Example 1 and 2-methyl-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.39 (s, 1H), 7.32 (m, 4H), 7.07 (d, 1H), 6.30 (br s, 1H), 3.13 (d, 3H), 2.20 (s, 3H).

MS m/z 239 [M⁺+1].

Example 47 [4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-carbamic acid benzyl ester

Using Method 2, the title compound was obtained in 19% yield from Example 1 and [4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenyl]-carbamic acid benzyl ester (from Combi-Blocks).

¹HNMR (400 MHz, DMSO-d₆) δ 7.67 (m, 1H), 7.44 (multiplets, 6H), 7.32 (multiplets, 5H), 7.17 (br s, 1H), 6.11 (br s, 1H), 5.32 (s, 2H), 3.17 (d, 3H).

MS m/z 374 [M⁺+1].

Example 48 Methyl-[3-(4-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine

Using Method 2, the title compound was obtained in 46% yield from Example 1 and 4-trifluoromethyl-phenylboronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 7.75 (m, 2H), 7.67 (d, 2H), 7.58 (s, 1H), 7.53 (d, 1H), 7.34 (d, 1H), 6.30 (br s, 1H), 3.20 (d, 3H).

MS m/z 293 [M⁺+1].

Example 49 [3-(2,4-Difluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 68% yield from Example 1 and 2,4-difluoro-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.64 (s, 1H), 7.44 (m, 3H), 7.37 (m, 1H), 7.50 (m, 2H), 6.20 (br s, 1H), 3.23 (d, 3H).

MS m/z 261 [M⁺+1].

Example 50 [3-(3,4-Dichloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 43% yield from Example 1 and 3,4-dichloro-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.41 (multiplets, 6H), 6.18 (br s, 1H), 3.19 (d, 3H).

MS m/z 293 [M⁺+1].

Example 51 [3-(3-Fluoro-4-methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 44% yield from Example 1 and (3,fluoro-4-methoxy)-phenylboronic acid (from Combi-Blocks).

¹HNMR (400 MHz, DMSO-d₆) δ 7.52 (m, 2H), 7.39 (d, 1H), 7.25 (multiplets, 2H), 7.05 (m, 1H), 6.29 (br s, 1H), 3.95 (s, 3H), 3.20 (d, 3H).

MS m/z 273 [M⁺+1].

Example 52 (3-Biphenyl-4-yl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine

Using Method 2, the title compound was obtained in 38% yield from Example 1 and biphenyl-4-yl-boronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.77 (d, 2H), 7.61 (m, 6H), 7.40 (multiplets, 4H), 6.15 (br s, 1H), 3.20 (d, 3H).

MS m/z 301 [M⁺+1].

Example 53 (3-Biphenyl-3-yl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine

Using Method 2, the title compound was obtained in 38% yield from Example 1 and biphenyl-3-yl-boronic acid (from Aldrich).

¹HNMR (400, MHz, DMSO-d₆) δ 7.74 (s, 1H), 7.50 (multiplets, 11H), 6.26 (br s, 1H), 3.23 (d, 3H).

MS m/z 301 [M⁺+1].

Example 54 [3-(4-Benzyloxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 35% yield from Example 1 and 4-benzyloxy-phenylboronic acid (from Lancaster).

¹HNMR (400 MHz, DMSO-d₆) δ 7.65 (m, 1H), 7.39 (multiplets, 9H), 7.09 (d, 2H), 6.18 (br s, 1H), 5.14 (s, 2H), 3.20 (d, 3H).

MS m/z 331 [M⁺+1].

Example 55 Methyl-(3-naphthalen-1-yl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using Method 2, the title compound was obtained in 85% yield from Example 1 and 1-naphthalene boronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.93 (m, 2H), 7.67 (s, 1H), 7.50 (multiplets, 5H), 7.29 (d, 1H), 6.95 (d, 1H), 6.47 (br s, 1H), 3.23 (d, 3H).

MS m/z 275 [M⁺+1].

Example 56 [3-(2-Chloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 33% yield from Example 1 and 2-chloro-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.66 (m, 1H), 7.44 (m, 1H), 7.38 (m, 4H), 7.15 (d, 1H), 6.30 (br s, 1H), 5.14 (s, 2H), 3.19 (d, 3H).

MS m/z 259 [M⁺+1].

Example 57 N-[3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]acetamide

Using Method 2, the title compound was obtained from Example 6 and 3-acetylamino-phenylboronic acid (from Lancaster).

¹HNMR (400 MHz, DMSO-d₆) δ 7.83 (m, 1H), 7.65 (d, 1H), 7.54 (s, 1H), 7.44 (m, 3H), 7.25 (m, 2H), 6.28 (br s, 1H), 2.96 (m, 1H), 2.26 (s, 3H), 0.93 (m, 2H), 0.67 (m, 2H).

MS m/z 308 [M⁺+1].

Example 58 Methyl-[3-(2-trifluoromethoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine

Using Method 2, the title compound was obtained in 55% yield from Example 1 and 2-trifluoromethoxy-phenylboronic acid (from Matrix).

¹HNMR (400 MHz, DMSO-d₆) δ 7.62 (s, 1H), 7.39 (multiplets, 5H), 7.20 (d, 1H), 6.46 (br s, 1H), 3.21 (d, 3H).

MS m/z 309 [M⁺+1].

Example 59 Methyl-[3-(3-trifluoromethoxy-phenyl)-imidazo[1,2-]pyrazin-8-yl]-amine

Using Method 2, the title compound was obtained in 32% yield from Example 1 and 3-trifluoromethoxy-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.60 (m, 5H), 7.41 (m, 1H), 7.23 (m, 1H), 6.19 (br s, 1H), 3.23 (d, 3H).

MS m/z 309 [M⁺+1].

Example 60 Cyclopropyl-{3-[3-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine

Synthesis of 4-{2-[3-(4,4,5,5-tetramethyl-[1,3,2]dioxaboralan-2-yl)-phenoxy]-ethyl}-morpholine:

To a stirred solution of 3-(4,4,5,5-tetramethyl-[1,3,2]dioxaboralan-2-yl)-phenol (1 g, 4.5 mmol from Aldrich) in DMF (100 mL) was added 4-(2-chloroethyl)-morpholine.HCl (930 mg, 5 mmol), Cs₂CO₃, and KI (40 mg, 0.24 mmol). The suspension was heated to 65° C. for 12 hours, at which time all starting material was consumed. The reaction was cooled, ethyl acetate was added (150 mL) and the organics were extracted with saturated sodium bicarbonate solution. The organics were separated, dried over MgSO₄, and dried in vacuo yielding 4-{2-[3-(4,4,5,5-tetramethyl-[1,3,2]dioxaboralan-2-yl)-phenoxy]-ethyl}-morpholine as a white crystalline solid in 78% yield.

¹H NMR (CDCl₃, 300 MHz) δ 1.34 (s, 12H), 2.56–2.59 (t, J=4.6, 4H), 2.8–2.88 (m, 2H), 3.71–3.74 (t, J=4.6, 2H), 4.14–4.18 (m, 2H), 7.2–7.4 (m, 4H).

Using Method 2, the Example 60 was obtained in 69% yield from Example 6 and 4-{2-[3-(4,4,5,5-tetramethyl-[1,3,2]dioxaboralan-2-yl)-phenoxy]-ethyl}-morpholine.

¹HNMR (400 MHz, DMSO-d₆) δ 7.63 (d, 1H), 7.52 (s, 1H), 7.47 (d, 1H), 7.38 (d, 1H), 7.13 (d, 1H), 7.04 (s, 1H), 6.95 (m, 1H), 6.26 (br s, 1H), 4.14 (m, 2H),3.73 (m, 4H), 2.97 (m, 1H), 2.82 (m, 2H), 2.60 (m, 4H), 2.90 (m, 2H), 0.67 (m, 2H).

MS m/z 380 [M⁺+1].

Example 61 3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol

Using Method 2, the title compound was obtained from Example 6 and 3-hydroxy-phenylboronic acid (from Combi-Blocks).

¹HNMR (400 MHz, DMSO-d₆) δ 9.68 (s, 1H), 7.63 (d, 1H), 7.57 (s, 1H), 7.31 (m, 2H), 6.95 (m, 2H), 6.76 (d, 1H), 2.89 (m, 1H), 0.70 (m, 2H), 0.63 (m, 2H).

MS m/z 267 [M⁺+1].

Example 62 Methyl-[3-(4-trifluoromethoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine

Using Method 2, the title compound was obtained in 42% yield from Example 1 and 3-trifluoromethoxy-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.49 (m, 4H), 7.35 (m, 3H), 6.32 (br s, 1H), 3.18 (d, 3H).

MS m/z 309 [M⁺+1].

Example 63 [3-(2-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 55% yield from Example 1 and 2-fluoro-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.61 (s, 1H), 7.40 (m, 3H), 7.19 (m, 3H), 6.29 (br s, 1H), 3.22 (d, 3H).

MS m/z 243 [M⁺+1].

Example 64 [3-(3,4-Difluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 40% yield from Example 1 and 3,4-difluoro-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.39 (multiplets, 2H), 7.24 (multiplets, 4H), 6.20 (br s, 1H), 3.20 (d, 3H).

MS m/z 261 [M⁺+1].

Example 65 (3-Benzo[1,3]dioxol-5-yl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine

Using Method 2, the title compound was obtained in 49% yield from Example 1 and 3,4-methylenedioxy-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.50 (m, 2H), 7.37 (d, 1H), 6.93 (m, 3H), 6.26 (br s, 1H), 6.09 (s, 2H), 3.19 (d, 3H).

MS m/z 269 [M⁺+1].

Example 66 [3-(3-Chloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 51% yield from Example 1 and 3-chloro-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.57 (m, 3H), 7.38 (m, 4H), 6.38 (br s, 1H), 3.21 (d, 3H).

MS m/z 259 [M⁺+1].

Example 67 [3-(4-Methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 59% yield from Example 1 and 4-methoxy-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.47 (m, 4H), 7.33 (d, 1H), 7.08 (d, 2H), 6.27 (br s, 1H), 3.89 (s, 3H), 3.20 (d, 3H).

MS m/z 255 [M⁺+1].

Example 68 [3-(2-Methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 31% yield from Example 1 and 2-methoxy-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.42 (multiplets, 4H), 7.20 (multiplets, 3H), 6.17 (br s, 1H), 3.82 (s, 3H), 3.18 (d, 3H).

MS m/z 255 [M⁺+1].

Example 69 Methyl-[3-(4-phenoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine

Using Method 2, the title compound was obtained in 51% yield from Example 1 and 4-phenoxy-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.52 (m, 4H), 7.33 (m, 3H), 7.12 (m, 5H), 6.29 (br s, 1H), 3.17 (d, 3H).

MS m/z 317 [M⁺+1].

Example 70 [3-(4-Benzyloxy-3-fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 22% yield from Example 1 and 3-fluoro-4-benzyloxy-phenylboronic acid (from Lancaster).

¹HNMR (400 MHz, DMSO-d₆) δ 7.35 (multiplets, 7H), 7.12 (multiplets, 4H), 6.09 (br s, 1H), 5.29 (s, 2H), 3.21 (d, 3H).

MS m/z 349 [M⁺+1].

Example 71 [3-(4-Isopropyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 60% yield from Example 1 and 4-isopropyl-phenylboronic acid (from Lancaster).

¹HNMR (400 MHz, DMSO-d₆) δ 7.55 (m, 2H), 7.50 (s, 1H), 7.42 (m, 2H), 7.33 (m, 2H), 6.37 (br s, 1H), 3.14 (d, 3H), 2.95 (m, 1H), 1.26 (d, 6H).

MS m/z 267 [M⁺+1].

Example 72 [3-(3,5-Bis-trifluoromethyl-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine

Using Method 2, the title compound was obtained in 37% yield from Example 6 and 3,5-bis(trifluoromethyl)phenylboronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 7.95 (m, 2H), 7.87 (s, 1H), 7.68 (s, 1H), 7.46 (m, 2H), 6.27 (br s, 1H), 2.95 (m, 1H), 0.93 (m, 2H), 0.67 (m, 2H).

MS m/z 387 [M⁺+1].

Example 73 Cyclopropyl-[3-(3,4-dichloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine

Using Method 2, the title compound was obtained in 29% yield from Example 6 and 3,4-dichloro-phenylboronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 7.53 (multiplets, 5H), 7.33 (d, 1H), 6.23 (br s, 1H), 2.93 (m, 1H), 0.94 (m, 2H), 0.70 (m, 2H).

MS m/z 320 [M⁺+1].

Example 74 3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-benzoic acid

Using Method 2, the title compound was obtained from Example 6 and 3-carboxy-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 8.22 (m, 1H), 8.12 (d, 1H), 7.76 (m, 1H), 7.62 (m, 3H), 7.52 (m, 2H), 6.24 (br s, 1H), 2.96 (m, 1H), 0.95 (m, 2H), 0.70 (m, 2H).

Example 75 Methyl-{3-[4-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine

Synthesis of 4-{2-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaboralan-2-yl)-phenoxy]-ethyl}-morpholine: To a stirred solution of 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaboralan-2-y)-phenol (1 g, 4.5 mmol) in DMF (100 mL), was added 4-(2-chloro-ethyl)-morpholine.HCl (930 mg, 5 mmol), Cs₂CO₃ and KI (40 mg, 0.24 mmol). The suspension was heated to 65° C. for 12 hours, at which time all starting material was consumed. The reaction was cooled, ethyl acetate was added (150 mL) and the organics were extracted with saturated sodium bicarbonate solution. The organics were separated, dried over MgSO₄, and dried in vacuo yielding 903 mg of 4-{2-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaboralan-2-yl)-phenoxy]-ethyl}-morpholine as a white crystalline solid (81%).

¹H NMR (CDCl₃, 300 MHz) δ 1.33 (s, 12H), 2.56–2.59 (t, J=4.6, 4H), 2.8–2.9 (m, 2H), 3.71–3.74 (t, J=4.7, 4H), 4.13–4.14 (m, 2H), 6.88–6.90 (d, J=8.5, 2H),7.72–7.75 (d, J=8.5, 2H).

Using Method 2, the title compound was obtained in 54% yield from Example 1 and 4-{2-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaboralan-2-yl)-phenoxy]-ethyl}-morpholine.

¹HNMR (400 MHz, DMSO-d₆) δ 7.42 (m, 4H), 7.33 (m, 1H), 7.03 (m, 2H), 6.32 (br s, 1H), 4.19 (t, 2H), 3.78 (m, 4H), 3.14 (d, 3H), 2.85 (t, 2H), 2.60 (m, 4H).

Example 76 Cyclopropyl-{3-[4-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine

Using Method 2, the title compound was obtained in 26% yield from Example 6 and 4-{2-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxaboralan-2-yl)-phenoxy]ethyl}-morpholine, which was prepared in Example 75.

¹HNMR (400 MHz, DMSO-d₆) δ 7.63 (m, 1H), 7.49 (m, 3H), 7.27 (s, 1H), 7.03 (m, 2H), 6.18 (br s, 1H), 4.14 (t, 2H), 3.70 (m, 4H), 2.95 (m, 1H), 2.80 (t, 2H), 2.60 (m, 4H), 0.90 (m, 2H), 0.63 (m, 2H).

Example 77 Cyclopropyl-[3-(4-dimethylamino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine

Using Method 2, the title compound was obtained in 26% yield from Example 6 and 4-dimethylamino-phenylboronic acid (from Aldrich)

¹HNMR (400 MHz, DMSO-d₆) δ 7.57 (m, 1H), 7.35 (m, 4H), 6.78 (m, 2H), 6.17 (br s, 1H), 3.05 (s, 6H), 2.91 (m, 1H), 0.95 (m, 2H), 0.71 (m, 2H).

Example 78 Cyclopropyl-[3-(4-phenoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine

Using Method 2, the title compound was obtained in 24% yield from Example 6 and 4-phenoxy-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.57 (m, 1H), 7.40 (m, 4H), 7.28 (m, 2H), 7.07 (m, 5H), 6.21 (br s, 1H), 2.90 (m, 1H), 0.89 (m, 2H), 0.63 (m, 2H).

Example 79 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone

Using Method 2, the title compound was obtained in 27% yield from Example 6 and 4-acetyl-phenylboronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 8.10 (d, 2H), 7.60 (m, 3H), 7.40 (m, 2H), 6.22 (br s, 1H), 2.95 (m, 1H), 2.62 (s, 3H), 0.90 (m, 2H), 0.67 (m, 2H).

Example 80 [4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]carbamic acid benzyl ester

Using Method 2, the title compound was obtained in 31% yield from Example 6 and [4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenyl]-carbamic acid benzyl ester (from Combi-Blocks).

¹HNMR (400 MHz, DMSO-d₆) δ 7.56 (m, 3H), 7.38 (m, 10H), 6.20 (br s, 1H), 5.25 (s, 2H), 2.92 (m, 1H), 0.93 (m, 2H), 0.60 (m, 2H).

Example 81 N-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-acetamide

Using Method 2, the title compound was obtained in 40% yield from Example 1 and [4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)acetanilide (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.70 (m, 3H), 7.47 (m, 4H), 7.33 (m, 1H), 6.04 (br s, 1H), 3.16 (d, 3H), 2.22 (s, 3H).

Example 82 [3-(3-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine

Using Method 2, the title compound was obtained in 38% yield from Example 6 and 3-aminophenylboronic acid (from TCI-US).

¹HNMR (400 MHz, DMSO-d₆) δ 7.64 (m, 1H), 7.52 (s, 1H), 7.45 (d, 1H), 7.27 (m, 1H), 6.93 (m, 1H), 6.82 (m, 1H), 6.73 (m, 1H), 6.18 (s, br, 1H), 3.80 (s, br, 2H), 2.95 (m, 1H), 0.90 (m, 2H), 0.64 (m, 2H).

MS m/z 266 [M⁺+1].

Example 83 [3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 46% yield from Example 1 and 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.48 (d, 1H), 7.42 (s, 1H), 7.30 (m, 3H), 6.78 (d, 2H), 6.00 (s, br, 1H), 3.85 (s, br, 2H), 3.20 (d, 3H).

MS m/z 240 [M⁺+1].

Example 84 Methyl-(3-naphthalen-2-yl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using Method 2, the title compound was obtained in 37% yield from Example 1 and 2-naphthaleneboronic acid (from TCI-US).

¹HNMR (400 MHz, DMSO-d₆) δ 7.95 (m, 2H), 7.84 (m, 2H), 7.64 (m, 2H), 7.54 (m, 2H), 7.43 (m, 2H), 6.18 (s, br, 1H), 3.20 (d, 3H).

MS m/z 275 [M⁺+1].

Example 85 4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-benzoic acid

Using Method 2, the title compound was obtained in 22% yield from Example 6 and 4-carboxy-phenylboronic acid (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 8.17 (d, 2H), 7.67 (m, 4H), 7.53 (d, 1H), 6.24 (s, br, 1H), 3.93 (s, br, 2H), 2.95 (m, 1H), 0.84 (m, 2H), 0.60 (m, 2H).

Example 86 [3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine

Using Method 2, the title compound was obtained in 58% yield from Example 6 and 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline (from Aldrich).

¹HNMR (400 MHz, DMSO-d₆) δ 7.53 (d, 1H), 7.42 (m, 2H), 7.28 (m, 2H), 6.77 (d, 2H), 6.32 (s, br, 1H), 3.93 (s, br, 2H0, 2.95 (m, 1H), 0.87 (m, 2H), 0.64 (m, 2H).

MS m/z 266 [M⁺+1].

Example 87 Methyl-{3-[3-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine

Using Method 2, the title compound was obtained in 70% yield from Example 1 and 3-(2-morpholin-4-yl-ethoxy)-phenylboronic acid, which was prepared in Example 60.

¹HNMR (400 MHz, DMSO-d₆) δ 7.58 (d, 1H), 7.53 (s, 1H), 7.39 (m, 2H), 7.11 (m, 1H), 7.06 (m, 1H), 6.93 (d, 1H), 6.33 (s, br, 1H), 4.16 (m, 2H), 3.70 (m, 4H), 3.15 (d, 3H), 2.84 (m, 2H), 2.59 (m, 4H).

MS m/z 354 [M⁺+1].

Example 88 [3-(3-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Using Method 2, the title compound was obtained in 60% yield from Example 1 and 3-aminophenylboronic acid (from TCI-US).

¹HNMR (400 MHz, DMSO-d₆) δ 7.64 (d, 1H), 7.52 (s, 1H), 7.38 (d, 1H), 7.27 (m, 1H), 6.93 (d, 1H), 6.84 (m, 1H), 6.74 (m, 1H), 5.98 (s, br, 1H), 3.16 (d, 3H).

MS m/z 240 [M⁺+1].

Example 89 3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol

Using Method 2, the title compound was obtained in 64% yield from Example 1 and 3-hydroxy-phenylboronic acid (from Combi-Blocks).

¹HNMR (400 MHz, DMSO-d₆) δ 7.69 (d, 1H), 7.54 (s, 1H), 7.35 (2×m, 2H), 7.05 (d, 1H), 6.97 (m, 1H), 6.87 (m, 1H), 3.07 (d, 3H).

MS m/z 241 [M⁺+1].

Example 90 4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-N-(2-morpholin-4-yl-ethyl)-benzamide

Step 1:

In a 2 dram vial under nitrogen, 500 mg (2.0 mmol) of E was added and dissolved in dichloromethane (DCM) (5 mL). 606 mg (6.0 mmol) of triethyl amine (TEA) was then added via syringe and the stirring mixture cooled to −15° C. 272 mg (2.0 mmol) of isobutyl chloroformate (IBC) was then added dropwise and the reaction mixture stirred for 5 minutes. After 5 minutes the formation of a white precipitate was observed, at which point the amine F was added and the solution allowed to warm to room temperature. Upon warming, the reaction was stirred for an additional 10 minutes. The reaction mixture was then diluted with dichloromethane (100 mL) and extracted with a saturated solution of sodium bicarbonate (2×25 mL). The organic layer was then dried over Na₂SO₄, filtered, and concentrated under vacuum. The colorless oil was then triturated using hexanes (50 mL) to provide G as a white solid. Yield: 53%. ¹H NMR (300 MHz, CDCl₃) δ 7.87 (d, J=8.2, 2H), 7.75 (d, J=8.2, 2H), 6.75 (br. s, 1H), 3.72 (t, J=4.6, 4H), 3.15 (q, J=5.7, 2H) 2.61 (t, J=6.0, 2H) 2.51 (t, J=4.5, 4H), 1.35 (s, 12H).

Step 2:

To a 2 dram vial, 100 mg (0.440 mmol) of Example 1, 190 mg (0.550 mmol) of the boronic ester G, and 51 mg (0.044 mmol) of palladium tetrakis triphenylphosphine were added. THF (2 mL) was then added followed by 1 N K₂CO₃(1 mL). The bi-phasic orange/yellow solution was then sealed and heated at 80° C. for 2 days. The crude mixture was then acidified with 2 N HCl (10 mL) and partitioned with ether (50 mL) and water (50 mL). The aqueous layer was then extracted twice with ether (50 mL) and the pH raised above 9 with 2 N NaOH (20 mL). The aqueous layer was then extracted twice with 75 mL of dichloromethane and the organic layers combined and concentrated under vacuum to provide a brown or yellow residue. The resulting residue was then purified by column chromatography (silica gel, 99:1 dichloromethane/MeOH) and isolated the title compound as an off-white solid. Yield: 29%. ¹H NMR (300 MHz, CDCl₃) δ 7.93 (d, J=8.3, 2H), 7.63–7.55 (m, 4H), 7.41 (d, J=4.8, 1H), 7.01 (broad s, 1H), 6.34, (broad s, 1H), 3.74 (t, J=4.6, 4H), 3.17 (q, J=5.7, 2H), 3.17 (d, J=5.0, 3H), 2.64 (t, J=6.0, 2H) 2.53 (t, J=5.0, 4H).

MS m/z 381 [M⁺+1].

Following compounds were prepared in the similar way as for preparing Example 90:

Example 91 4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-N-(3-morpholin-4-yl-propyl)-benzamide

¹HNMR (400 MHz, DMSO-d₆) δ 8.08 (m, br, 1H), 7.95 (d, 2H), 7.55 (2×m, 4H), 7.42 (d, 1H), 6.00 (m, br, 1H), 3.74 (m, 4H), 3.58 (m, 2H), 3.18 (d, 3H), 2.52 (2×m, 6H), 1.84 (m, 2H).

MS m/z 395 [M⁺+1].

Example 92 4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-N-(3-pyrrolidin-1-yl-propyl)-benzamide

¹HNMR (400 MHz, DMSO-d₆) δ 9.00 (br s, 1H), 7.92 (d, 2H), 7.59 (m, 4H), 7.42 (d, 1H), 5.99 (br s, 1H), 3.61 (m, 2H), 3.17 (d, 3H), 2.73 (m, 2H), 2.58 (m, 4H), 1.85 (m, 6H).

MS m/z 379 [M⁺+1].

Example 93 1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea

Step 1:

A 1 L round bottomed flask with a magnetic stir bar was charged with 3-amino boronic acid (H) (10 g, 0.065 mol), pinacol (I) (9.53 g, 0.080 mol) and magnesium sulfate (23.3 g, 0.193 mol). Ether (500 mL) was added to the mixture and the solution was stirred at room temperature for 5 h (until TLC showed complete disappearance of starting material). The reaction mixture was filtered and the organic layer was washed with brine (2×100 mL). The combined organic layer was dried over Na₂SO₄ and condensed to give a white solid J (15.11 g, 94% crude yield).

¹H NMR (CDCl₃) δ 1.33 (s, 12H), 3.64 (bs, 2H), 6.7 (m, 1H), 7.12–7.25 (m, 3H).

Step 2:

A 1 L round bottomed flask fitted with a water-cooled condenser, was charged with J (10 g, 0.04 mol), triphosgene (4.38 g, 0.147 mol) and triethylamine (12 mL). Carbon tetrachloride (500 mL) was added and the reaction was gently heated to reflux. The reflux was continued for 7 h under a positive nitrogen pressure. The reaction mixture was cooled and washed with water (2×100 mL). The organic layer was dried over Na₂SO₄ and condensed. The oil thus obtained was taken in heptane (200 mL), filtered and condensed to give pure K (8.62 g, 77% crude yield).

¹H NMR (CDCl₃) δ 1.34 (s, 12H), 7.15 (d, 1H, J=7.9 Hz), 7.29–7.34 (t, 1H, J=7.6 Hz), 7.53 (s, 1H), 7.61 (d, 1H, J=7.3 Hz).

Step 3:

To a stirring solution of K (1 g, 3.8 mmol) in methylene chloride (10 mL) was added 3-amino (propyl) morpholine (603 mg, 4.18 mmol) and triethylamine (0.8 mL). The reaction mixture was refluxed for 12 h. The solution was cooled and condensed. The crude was column purified on silica gel (1:10 methanol in methylene chloride) to get L (900 mg, 62% yield).

¹H NMR (CDCl₃) δ 1.33 (s, 12H), 1.65–1.73 (m, 2H), 2.38–2.45 (m, 6H), 3.32–3.38 (m, 2H), 3.56–3.60 (m, 4H), 5.5 (bs, 1H), 6.47 (bs, 1H), 7.31–7.36 (m, 1H), 7.52–7.56 (m, 3H).

Step 4:

To a degassed solution of aqueous THF (9:1 THF:water) were sequentially added L (565 mg, 1.45 mmol), Example 1 (300 mg, 1.32 mmol), K₂CO₃ (546 mg, 3.96 mmol) and Pd(Ph₃P)₄ (15 mg, 1 mol %). The reaction was refluxed under nitrogen for 48 h. The reaction mixture was cooled and condensed. The crude was twice column purified on normal phase and reverse phase silica gel to get pure title compound.

¹HNMR (400 MHz, DMSO-d₆) δ 7.59 (m, 2H), 7.50 (s, 1H), 7.35 (m, 3H), 7.14 (m, 2H), 6.06 (m, 1H), 3.62 (m, 2H), 3.34 (m, 2H), 3.15 (d, 3H), 2.44 (m, 6H), 1.71 (m, 2H).

The following compounds were prepared using similar method as for synthesizing Example 93:

Example 94 (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic

acid [4-(8-cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide

¹HNMR (400 MHz, DMSO-d₆) δ 11.28 (br s, 1H), 7.61 (d, 1H), 7.49 (multiplets, 6H), 6.23 (br s, 1H), 3.90 (multiplets, 2H), 3.39 (m, 1H), 2.95 (m, 2H), 2.87 (m, 2H), 2.64 (m, 2H), 2.50 (d, 1H), 2.15 (m, 1H), 2.03 (m, 4H), 1.84 (m, 2H), 1.78 (m, 1H), 0.93 (m, 2H), 0.70 (m, 2H).

MS m/z 446 [M⁺+1].

Example 95 (S)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic acid [4-(8-cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide

¹HNMR (400 MHz, DMSO-d₆) δ 7.58 (d, 1H), 7.43 (multiplets, 6H), 6.18 br s, 1H), 3.93 (multiplets, 2H), 3.40 (m, 1H), 3.00 (multiplets, 2H), 2.87 (m, 2H), 2.64 (m, 2H), 2.50 (d, 1H), 2.13 (m, 1H), 1.91 (m, 4H), 1.79 (m, 4H), 1.65 (m, 2H), 0.93 (m, 2H), 0.70 (m, 2H). MS m/z 446 [M⁺+1].

Example 96 (S)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic acid [4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide

¹HNMR (400 MHz, DMSO-d₆) δ 7.53 (m, 4H), 7.37 (m, 3H), 6.10 (m, 1H), 3.91 (m, 2H), 3.40 (m, 1H), 3.14 (d, 3H), 2.95 (m, 2H), 2.86 (m, 2H), 2.66 (m, 2H), 2.53 (m, 2H), 2.12 (m, 1H), 1.97 (m, 3H), 1.86 (m, 2H), 1.69 (m, 1H).

MS m/z 420 [M⁺+1].

Example 97 1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea

¹HNMR (400 MHz, DMSO-d₆) δ 7.73 (br s, 1H), 7.47 (m, 6H), 7.37 (d, 1H), 6.21 (m, 1H), 5.96 (br s, 1H), 3.65 (m, 4H), 3.36 (m, 2H), 3.16 (d, 2H), 2.46 (m, 4H), 1.75 (m, 2H).

MS m/z 410 [M⁺+1].

Example 98 (S)-3-Hydroxy-pyrrolidine-1-carboxylic acid [4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide

¹HNMR (400 MHz, DMSO-d₆) δ 7.68 (m, 3H), 7.50 (m, 3H), 7.30 (d, 1H), 4.47 (br s, 1H), 3.63 (m, 2H), 3.48 (m, 1H), 3.31 (m, 2H), 3.07 (d, 3H), 2.09 (m, 2H).

MS m/z 353 [M⁺+1].

Example 99 (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic acid [3-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide

¹HNMR (400 MHz, DMSO-d₆) δ 7.68 (m, 2H), 7.55 (s, 1H), 7.38 (m, 3H), 7.11 (m, 1H), 6.08 (m, 1H), 3.87 (m, 2H), 3.39 (m, 1H), 3.17 (d, 3H), 2.96 (m, 1H), 2.85 (m, 2H), 2.65 (m, 2H), 2.48 (m, 1H), 2.14 (m, 1H), 2.83 (m, 6H), 1.65 (m, 1H).

MS m/z 420 [M⁺+1].

Example 100 1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]3-(3-pyrrolidin-1-yl-propyl)-urea

¹HNMR (400 MHz, DMSO-d₆) δ 8.59 (br s, 1H), 7.47 (m, 3H), 7.42 (m, 2H), 7.33 (m, 2H), 6.26 (m, 1H), 6.04 (br s, 1H), 3.36 (m, 2H), 3.12 (d, 3H), 2.51 (m, 6H), 1.72 (m, 6H).

MS m/z 394 [M⁺+1].

Example 101 4-Pyrrolidin-1-yl-piperidine-1-carboxylic acid [4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide

¹HNMR (400 MHz, DMSO-d₆) δ 7.48 (m, 4H), 7.39 (d, 1H), 7.42 (m, 2H), 6.53 (br s, 1H), 5.99 (br s, 1H), 4.01 (m, 2H), 3.12 (d, 3H), 3.00 (m, 2H), 2.99 (m, 4H), 2.19 (m, 1H), 1.96 (m, 2H), 1.77 (m, 4H), 1.57 (m, 2H).

MS m/z 420 [M⁺+1].

Example 102 1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea

¹HNMR (400 MHz, DMSO-d₆) δ 7.49 (m, 6H), 7.39 (d, 1H), 5.99 (m, 1H), 5.28 (m, 1H), 3.67 (m, 4H), 3.40 (m, 2H), 3.12 (d, 3H), 3.00 (m, 2H), 2.49 (m, 4H).

MS m/z 396 [M⁺+1].

Example 103 4-Hydroxy-piperidine-1-carboxylic acid [4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide

¹HNMR (400 MHz, DMSO-d₆) δ 7.65 (d, 1H), 7.49 (m, 5H), 7.27 (d, 1H), 3.93 (m, 2H), 3.83 (m, 1H), 3.29 (m, 1H), 3.18 (m, 1H), 3.04 (d, 3H), 1.89 (m, 2H), 1.53 (m, 2H).

MS m/z 367 [M⁺+1].

Example 104 (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic acid [3-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide

¹HNMR (400 MHz, DMSO-d₆) δ 7.64 (m, 2H), 7.50 (s, 1H), 7.34 (m 3H), 7.08 (m, 1H), 5.97 (m, 1H), 3.85 (m, 2H), 3.36 (m, 1H), 3.18 (d, 3H), 2.96, 2.85, 2.64, 2.50 (4×m, 6H), 2.12, 1.90, 1.80, 1.64, 1.37 (5×m, 10H).

MS m/z 420 [M⁺+1].

Example 105 4-Hydroxy-piperidine-1-carboxylic acid [3-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide

¹HNMR (400 MHz, DMSO-d₆) δ 7.67 (m, 2H), 7.55 (s, 1H), 7.40 (m, 2H), 7.29 (m, 1H), 7.20 (m, 1H), 6.49 (m, 1H), 6.00 (m, 1H), 3.94 (m, 1H), 3.83 (m, 2H), 3.23 (m, 2H), 3.15 (d, 3H), 1.98 (m, 2H), 1.64 (m, 4H).

MS m/z 367 [M⁺+1].

Example 106 1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea

¹HNMR (400 MHz, DMSO-d₆) δ 7.63 (m, 2H), 7.53 (s, 1H), 7.40 (m, 3H), 7.19 (m, 1H), 6.04 (m, 1H), 5.32 (m, 1H), 3.68 (m, 4H), 3.38 (m, 2H), 3.16 (d, 3H), 2.56 (m, 2H), 2.47 (m, 4H).

MS m/z 396 [M⁺+1].

Example 107 1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea

¹HNMR (400 MHz, DMSO-d₆) δ 7.60 (m, 2H), 7.50 (s, 1H), 7.31 (m, 3H), 7.09 (m, 1H), 6.11 (m, 1H), 5.91 (m, 1H), 3.36 (m, 2H), 3.14 (d, 3H), 2.69 (m, 2H), 2.53 (m, 4H), 1.75 (m, 4H).

MS m/z 380 [M⁺+1].

Example 108 1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea

¹HNMR (400 MHz, DMSO-d₆) δ 8.62 (br s, 1H), 7.58 (m, 2H), 7.44 (s, 1H), 7.28 (m, 2H), 7.09 (m, 2H), 6.38 (m, 1H), 6.14 (br s, 1H), 3.31 (m, 2H), 3.12 (d, 3H), 2.51 (m, 2H), 2.43 (m, 4H), 1.71 (m, 6H).

MS m/z 394 [M⁺+1].

Example 109 1-[3-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea

¹HNMR (400 MHz, DMSO-d₆) δ 7.59 (m, 2H), 7.50 (s, 1H), 7.35 (m, 3H), 7.14 (m, 2H), 6.06 (m, 1H), 3.62 (m, 2H), 3.34 (m, 2H), 3.15 (d, 3H), 2.44 (m, 6H), 1.71 (m, 2H).

Example 110 (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic acid [4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide

¹HNMR (400 MHz, DMSO-d₆) δ 7.53 (multiplets, 4H), 7.50 (multiplets, 3H), 7.27 (s, 1H), 6.00 (br s, 1H), 4.00 (m, 1H), 3.86 (m, 1H), 3.37 (m, 1H), 3.16 (d, 3H), 2.97 (m, 1H), 2.87 (m, 2H), 2.68 (m, 2H), 2.54 (m, 1H), 2.16 (m, 1H), 1.97 (m, 4H), 1.84 (m, 2H), 1.67 (m, 1H).

MS m/z 420 [M⁺+1].

Example 111 (R)-2-Dimethylaminomethyl-pyrrolidine-1-carboxylic acid [4-(8-methylaamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide

¹HNMR (400 MHz, DMSO-d₆) δ 7.50 (multiplets, 5H), 7.37 (d, 1H), 7.27 (s, 1H), 6.28 (br s, 1H), 6.05 (br m, 1H), 3.74 (m, 3H), 3.46 (m, 1H), 3.24 (m, 1H), 3.16 (d, 3H), 2.82 (m, 1H), 2.64 (m, 1H), 2.32 (s, 6H), 2.19 (m, 1H), 1.92 (m, 1H).

Example 112 1-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea

¹HNMR (400 MHz, DMSO-d₆) δ 7.68 (d, 1H), 7.53 (multiplets, 5H), 7.30 (d, 1H), 3.79 (m, 2H), 3.52 (multiplets, 4H), 3.29 (m, 1H), 3.06 (d, 3H), 2.34 (m, 2H), 2.09 (m, 2H), 1.81 (m, 1H).

MS m/z 380 [M⁺+1].

Example 113 (R)-3-Hydroxy-pyrrolidine-1-carboxylic acid [4-(8-methylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide

¹HNMR (400 MHz, DMSO-d₆) δ 7.48 (multiplets, 3H), 7.37 (d, 1H), 7.27 (s, 3H), 6.30 (br s, 1H), 5.99 (br m, 1H), 3.65 (m, 4H), 3.19 (d, 3H), 2.11 (m, 1H), 1.72 (m, 2H).

MS m/z 353 [M⁺+1].

Example 114 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea

¹HNMR (400 MHz, DMSO-d₆) δ 8.46 (br s, 1H), 7.46 (multiplets, 7H), 6.28 (m, 1H), 5.83 (br s, 1H), 3.35 (m, 2H), 2.94 (m, 1H), 2.80 (m, 1H), 2.46 (m, 5H), 1.73 (m, 6H), 0.90 (m, 2H), 0.68 (m, 2H).

MS m/z 420 [M⁺+1].

Example 115 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea

¹HNMR (400 MHz, DMSO-d₆) δ 7.53 (d, 1H), 7.42 (multiplets, 6H), 7.07 br s, 1H), 6.19 (m, 1H), 5.71 (br s, 1H), 3.68 (m, 4H), 3.35 (m, 2H), 2.92 (m, 1H), 2.46 (m, 5H), 1.73 (m, 3H), 0.90 (m, 2H), 0.68 (m, 2H).

Example 116 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea

¹HNMR (400 MHz, DMSO-d₆) δ 7.45 (multiplets, 7H), 6.20 br s, 1H), 6.19 (br s, 1H), 5.71 (br s, 1H), 3.43 (m, 2H), 2.96 (m, 1H), 2.73 (m, 2H), 2.60 (m, 4H), 1.84 (m, 4H), 0.90 (m, 2H), 0.67 (m, 2H).

MS m/z 406 [M⁺+1].

Example 117 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea

¹HNMR (400 MHz, DMSO-d₆) δ 7.72 (br m, 1H), 7.53 (multiplets, 7H), 6.26 br s, 1H), 5.53 (br s, 1H), 3.62 (m, 4H), 3.43 (m, 2H), 2.96 (m, 1H), 2.57 (multiplets, 4H), 1.91 (m, 2H), 0.78 (m, 2H), 0.60 (m, 2H).

MS m/z 422 [M⁺+1].

Example 118 [5-(4-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

Step 1: Synthesis of (5-Bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (intermediate M)

To a solution of (3-bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (Example 1) (2.4 g, 11.9 mmol) in methanol (160 ml) was added Pd-C (10% wt. 0.1 eq). The mixture was hydrogenated at rt overnight, filtered, and washed with hot methanol. The organics were combined and concentrated to afford 2.8 g of crude imidazo[1,2-a]pyrazin-8-yl-methyl-amine (M).

¹HNMR (400 MHz, DMSO-d₆) δ 7.83 (d, 1H), 7.72 (d, 1H), 7.45 (d, 1H), 7.21 (d, 1H), 2.90 (s, 3H).

MS m/z 149 [M⁺+1].

Step 2: Synthesis of 3,5-dibromo-imidazo[1,2-a]pyrazin-8-yl)-methylaminie (Intermediate N) and 5-bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (intermediate O)

To a solution of imidazo[1,2-a]pyrazin-8-yl-methyl-amine (M) (2.0 g, 13.4 mmol) in HOAc (16 ml) was added NaOAc (2 g). The mixture was cooled to 0° C. and a solution of Br₂ (620 ml, 0.9 eq) in HOAc (2 ml) was added slowly. The mixture was stirred and gradually warmed to rt, stirred overnight. The mixture was concentrated and purified over silica gel column to afford 515 mg of (3,5-dibromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine intermediate N and 777 mg of 5-bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (intermediate O).

Intermediate N: ¹H NMR (400 MHz, CDCl₃) δ 3.04, 3.05 (2×s, 3H), 6.05 (brs, 1H), 7.33 (s, 1H), 7.36 (s, 1H).

MS m/z 227 [M⁺].

Intermediate O: ¹H NMR (400 MHz, CDCl₃) δ 3.09, 3.11 (2×s, 3H), 6.35 (brs, 1H), 7.43 (s, 1H), 7.51 (s, 1H), 7.64 (s, 1H).

MS m/z 227 [M+1].

Step 3: Synthesis of [5-(4-Fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine (Example 118)

To a solution of (5-bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (intermediate O) (68 mg, 0.3 mmol) in DMF (4 ml) and water (2 ml) was added 4-fluorobenzene boronic acid (84 mg, 0.6 mmol), K₂CO₃ (165 mg 1.2 mmol), and Pd(PPh₃)₄ (35 mg, 0.1 eq). The mixture was heated at 170° C. in microwave for 6 min. The mixture was purified on a silica gel column to give the title compound.

¹HNMR (400 MHz, DMSO-d₆) δ 7.54 (m, 4H), 7.33 (s, 1H), 7.23 (m, 2H), 3.2 (d, 3H).

MS m/z 243 [M⁺+1].

The follow compounds were prepared using the same procedure as for synthesis of Example 118:

Example 119 Methyl-(5-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine

¹HNMR (400 MHz, DMSO-d₆) δ 7.63 (d, 2H), 7.58–7.45 (m, 6H), 7.37 (s, 1H), 3.2 (d, 3H).

MS m/z 225 [M⁺+1].

Example 120 Methyl-(5-thiophen-3-yl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using procedure for Example 127, the title compound was obtained from (5-bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (Example 91), and 3-thiophenylboronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 7.67 (s, 1H), 7.52 (m, 3H), 7.43 (s, 1H), 7.36 (d, J=4.8 Hz, 1H), 6.12 (br s, 1H), 3.19, 3.20 (2×s, 3H)

MS m/z 231 [M⁺+1].

Example 121 4-(8-Methylamino-imidazo[1,2-a]pyrazin-5-yl)-phenol

¹HNMR (400 MHz, DMSO-d₆) δ 8.72 (s, 1H), 7.68 (s, 1H), 7.46 (2×m, 3H), 7.22 (s, 1H), 7.01 (m, 2H), 6.63 (s, br, 1H), 3.74 (m, 4H), 3.13 (d, 3H).

MS m/z 241 [M⁺+1].

Example 122 N-[4-(8-Methylamino-imidazo[1,2-a]pyrazin-5-yl)-phenyl]-acetamide

¹HNMR (400 MHz, DMSO-d₆) δ 10.12 (s, br, 1H), 7.77 (s, 1H), 7.72 (d, 2H), 7.50 (m, 4H), 7.25 (s, 1H), 2.95 (d, 3H), 2.07 (s, 3H).

MS m/z 282 [M⁺+1].

Example 123 [3,5-Bis-(4-fluoro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-methyl-amine

¹HNMR (400 MHz, DMSO-d₆) δ 7.45 (s, 1H), 6.97 (m, 2H), 6.87 (m, 2H), 6.73 (m, 4H), 6.18 (s, br, 1H), 3.23 (d, 3H).

MS m/z 337 [M⁺+1].

Example 124 (3,5-Diphenyl-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine

¹HNMR (400 MHz, DMSO-d₆) δ 7.49 (s, 1H), 7.30 (s, 1H), 7.00 (m, 8H), 6.91 (m, 1H), 6.89 (m, 1H), 6.16 (s, br, 1H), 3.23 (d, 3H).

MS m/z 301 [M⁺+1].

Example 125 Methyl-(6-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine

Step 1: Synthesis of 3,5-Dibromo-pyrazin-2-ylamine—Intermediate Q

To a solution of aminopyrazine (P) (1.902 g, 20 mmol, 1 eq.) in chloroform (160 ml) was added pyridine (3.4 ml, 42 mmol, 2.1 eq.) and bromine (2.15 ml, 2.1 eq.). The mixture was stirred at rt for 2 hours. The mixture was then diluted with DCM, washed with water, dried over sodium sulfate and concentrated to afford 2.583 g of title compound (yield 51%) as a light brown solid.

¹HNMR (400 MHz, DMSO-d₆) δ 8.12 (s, 1H), 6.98 (br s, 2H).

Step 2: Synthesis of 6,8-Dibromo-imidazo[1,2-a]pyrazine—Intermediate R

Using procedure for Intermediate C, the title compound was obtained from 3,5-dibromo-pyrazin-2-ylamine (Intermediate Q), and bromoacetaldehyde diethylacetal.

¹HNMR (400 MHz, DMSO-d₆) δ 9.00 (s, 1H), 8.20 (d, 1H), 7.87 (d, 1H).

MS m/z 278 [M⁺+1].

Step 3: Synthesis of (6-Bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (Intermediate S)

Using procedure for Example 1, the title compound was obtained in 94% yield from 6,8-dibromo-imidazo[1,2-a]pyrazine (Intermediate R) and methylamine.

¹HNMR (400 MHz, DMSO-d₆) δ 7.98 (s, 1H), 7.95 (d, 1H), 7.79 (d, 1H), 7.47 (d, 1H), 2.89 (d, 3H).

MS m/z 228 [M⁺+1].

Step 4: Methyl-(6-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine

Using Suzuki coupling procedure for Example 10, the title compound was obtained in 36% yield from (6-bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (Example 30), and benzene boronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 8.37 (s, 1H), 7.98 (d, 2H), 7.85 (d, 1H), 7.55 (m, 1H), 7.49 (s, 1H), 7.43 (m, 2H), 7.33 (m, 1H), 3.00 (d, 3H).

MS m/z 225 [M⁺+1].

The following compounds were prepared using the same procedure as for synthesizing Example 125:

Example 126 4-(8-Methylamino-imidazo[1,2-a]pyrazin-6-yl)-phenol

Using method 1 for Suzuki coupling reaction, the title compound was obtained in 24% yield from (6-bromo-imidazo[1,2-a]pyrazin-8-yl)-methyl-amine (Intermediate S) and 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenol.

¹HNMR (400 MHz, DMSO-d₆) δ 9.51 (s, 1H), 8.18 (s, 1H), 7.80 (d, 2H), 7.78 (s, 1H), 7.45 (s, 2H), 6.80 (d, 2H), 3.01 (d, 3H).

MS m/z 241 [M⁺+1].

Example 127 6-Phenyl-imidazo[1,2-a]pyrazin-8-ylamine

Using procedure for preparing Example 125, the title compound was obtained from intermediate S and benzene boronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 8.38 (s, 1H), 7.91 (d, 2H), 7.86 (s, 1H), 7.51 (s, 1H), 7.42 (m, 2H), 7.33 (m, 1H), 6.99 (br s, 2H).

MS m/z 211 [M⁺+1].

Example 128 Dimethyl-(3-phenyl-imidazo[1,2-a]pyrazin-5-yl-amine

Using method 1 for Suzuki coupling reaction, the title compound was obtained in 55% yield from [(3-Bromo-imidazo[1,2-a]pyrazin-5-yl)-dimethyl-amine (see Example 18) and phenyl boronic acid.

¹HNMR (400 MHz, DMSO-d₆) δ 8.35 (d, 1H), 7.75 (d, 1H), 7.50 (s, 1H), 7.40 (m, 1H), 6.88 (d, 1H), 6.22 (br s, 1H), 3.95 (s, 3H), 3.17 (d, 3H).

Biological Examples

The following assays are employed to find those compounds demonstrating the optimal degree of the desired activity.

A. Assay Procedures.

The following assays may be used to determine the level of activity and effect of the different compounds of the present invention on one or more of the PKs. Similar assays can be designed along the same lines for any PK using techniques well known in the art.

Several of the assays described herein are performed in an ELISA (Enzyme-Linked Immunosorbent Sandwich Assay) format (Voller, et al., 1980, “Enzyme-Linked Immunosorbent Assay,” Manual of Clinical Immunology, 2d ed., Rose and Friedman, Am. Soc. Of Microbiology, Washington, D.C., pp. 359–371). The general procedure is as follows: a compound is introduced to cells expressing the test kinase, either naturally or recombinantly, for a selected period of time after which, if the test kinase is a receptor, a ligand known to activate the receptor is added. The cells are lysed and the lysate is transferred to the wells of an ELISA plate previously coated with a specific antibody recognizing the substrate of the enzymatic phosphorylation reaction. Non-substrate components of the cell lysate are washed away and the amount of phosphorylation on the substrate is detected with an antibody specifically recognizing phosphotyrosine compared with control cells that were not contacted with a test compound.

The presently preferred protocols for conducting the ELISA experiments for specific PKs is provided below. However, adaptation of these protocols for determining the activity of compounds against other RTKs, as well as for CTKs and STKs, is well within the scope of knowledge of those skilled in the art.

Other assays described herein measure the amount of DNA made in response to activation of a test kinase, which is a general measure of a proliferative response. The general procedure for this assay is as follows: a compound is introduced to cells expressing the test kinase, either naturally or recombinantly, for a selected period of time after which, if the test kinase is a receptor, a ligand known to activate the receptor is added. After incubation at least overnight, a DNA labeling reagent such as 5-bromodeoxyuridine (BrdU) or H³-thymidine is added. The amount of labeled DNA is detected with either an anti-BrdU antibody or by measuring radioactivity and is compared to control cells not contacted with a test compound.

GST-FLK-1 Bioassy

This assay analyzes the tyrosine kinase activity of GST-Flk1 on poly(glu,tyr) peptides.

Materials and Reagents:

-   1. Corning 96-well ELISA plates (Corning Catalog No. 5805–96). -   2. poly(glu,tyr) 4:1, lyophilizate (Sigma Catalog # P0275). -   3. Preparation of poly(glu,tyr)(pEY) coated assay plates: Coat 2     ug/well of poly(glu,tyr)(pEY) in 100 ul PBS, hold at room     temperature for 2 hours or at 4° C. overnight. Cover plates well to     prevent evaporation. -   4. PBS Buffer: for 1 L, mix 0.2 g KH₂PO₄, 1.15 g Na₂HPO₄, 0.2 g KCl     and 8 g NaCl in approx. 900 ml dH₂O. When all reagents have     dissolved, adjust the pH to 7.2 with HCl. Bring total volume to 1 L     with dH₂O. -   5. PBST Buffer: to 1 L of PBS Buffer, add 1.0 ml Tween-20. -   6. TBB-Blocking Buffer: for 1 L, mix 1.21 g TRIS, 8.77 g NaCl, 1 ml     TWEEN-20 in approximately 900 ml dH₂O. Adjust pH to 7.2 with HCl.     Add 10 g BSA, stir to dissolve. Bring total volume to 1 L with dH₂O.     Filter to remove particulate matter. -   7. 1% BSA in PBS: To make a 1× working solution, add 10 g BSA to     approx. 990 ml PBS buffer, stir to dissolve. Adjust total volume to     1 L with PBS buffer, filter to remove particulate matter. -   8. 50 mM Hepes pH 7.5. -   9. GST-Flk1cd purified from sf9 recombinant baculovirus     transformation (SUGEN, Inc.). -   10. 4% DMSO in dH₂O. -   11. 10 mM ATP in dH₂O. -   12. 40 mM MnCl₂ -   13. Kinase Dilution Buffer (KDB): mix 10 ml Hepes (pH 7.5), 1 ml 5M     NaCl, 40 μL 100 mM sodium orthovanadate and 0.4 ml of 5% BSA in dH₂O     with 88.56 ml dH₂O. -   14. NUNC 96-well V bottom polypropylene plates, Applied Scientific     Catalog # AS-72092 -   15. EDTA: mix 14.12 g ethylenediaminetetraacetic acid (EDTA) to     approx. 70 ml dH₂O. Add 10 N NaOH until EDTA dissolves. Adjust pH to     8.0. Adjust total volume to 100 ml with dH₂O. -   16. 1⁰ Antibody Dilution Buffer: mix 10 ml of 5% BSA in PBS buffer     with 89.5 ml TBST. -   17. Anti-phosphotyrosine monoclonal antibody conjugated to     horseradish peroxidase (PY99 HRP, Santa Cruz Biotech). -   18. 2,2′-Azinobis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS, Moss,     Cat. No. ABST). -   19. 10% SDS.     Procedure: -   1. Coat Corning 96-well ELISA plates with 2 μg of polyEY peptide in     sterile PBS as described in step 3 of Materials and Reagents. -   2. Remove unbound liquid from wells by inverting plate. Wash once     with TBST. Pat the plate on a paper towel to remove excess liquid. -   3. Add 100 μl of 1% BSA in PBS to each well. Incubate, with shaking,     for 1 hr. at room temperature. -   4. Repeat step 2. -   5. Soak wells with 50 mM HEPES (pH7.5) (150 μl/well). -   6. Dilute test compound with dH₂O/4% DMSO to 4 times the desired     final assay concentration in 96-well polypropylene plates. -   7. Add 25 μl diluted test compound to ELISA plate. In control wells,     place 25 μl of dH₂O/4% DMSO. -   8. Add 25 μl of 40 mM MnCl₂ with 4× ATP (2 μM) to each well. -   9. Add 25 μl 0.5M EDTA to negative control wells. -   10. Dilute GST-Flk1 to 0.005 μg (5 ng)/well with KDB. -   11. Add 50 μl of diluted enzyme to each well. -   12. Incubate, with shaking, for 15 minutes at room temperature. -   13. Stop reaction by adding 50 μl of 250 mM EDTA (pH 8.0). -   14. Wash 3× with TBST and pat plate on paper towel to remove excess     liquid. -   15. Add 100 μl per well anti-phosphotyrosine HRP conjugate, 1:5,000     dilution in antibody dilution buffer. Incubate, with shaking, for 90     min. at room temperature. -   16. Wash as in step 14. -   17. Add 100 μl of room temperature ABTS solution to each well. -   18. Incubate, with shaking, for 10 to 15 minutes. Remove any     bubbles. -   19. Stop reaction by adding 20 μl of 10% SDS to each well. -   20. Read results on Dynatech MR7000 ELISA reader with test filter at     410 nM and reference filter at 630 nM.

PYK2 Bioassay

This assay is used to measure the in vitro kinase activity of HA epitope-tagged full length pyk2 (FL.pyk2-HA) in an ELISA assay.

Materials and Reagents:

-   1. Corning 96-well Elisa plates. -   2. 12CA5 monoclonal anti-HA antibody (SUGEN, Inc.) -   3. PBS (Dulbecco's Phosphate-Buffered Saline (Gibco Catalog #     450–1300EB) -   4. TBST Buffer: for 1 L, mix 8.766 g NaCl, 6.057 g TRIS and 1 ml of     0.1% Triton X-100 in approx. 900 ml dH₂O. Adjust pH to 7.2, bring     volume to 1 L. -   5. Blocking Buffer: for 1 L, mix 100 g 10% BSA, 12.1 g 100 mM TRIS,     58.44 g 1M NaCl and 10 mL of 1% TWEEN-20. -   6. FL.pyk2-HA from sf9 cell lysates (SUGEN, Inc.). -   7. 4% DMSO in MilliQue H₂O. -   8. 10 mM ATP in dH₂O. -   9. 1M MnCl₂. -   10. 1M MgCl₂. -   11. 1M Dithiothreitol (DTT). -   12. 10× Kinase buffer phosphorylation: mix 5.0 ml 1M Hepes (pH 7.5),     0.2 ml 1M MnCl₂, 1.0 ml 1 M MgCl₂, 1.0 ml 10% Triton X-100 in 2.8 ml     dH₂O. Just prior to use, add 0.1 ml 1M DTT. -   13. NUNC 96-well V bottom polypropylene plates. -   14. 500 mM EDTA in dH₂O. -   15. Antibody dilution buffer: for 100 mL, 1 mL 5% BSA/PBS and 1 mL     10% Tween-20 in 88 mL TBS. -   16. HRP-conjugated anti-Ptyr PY99), Santa Cruz Biotech Cat. No.     SC-7020. -   17. ABTS, Moss, Cat. No. ABST-2000. -   18. 10% SDS.     Procedure: -   1. Coat Corning 96 well ELISA plates with 0.5 μg per well 12CA5     anti-HA antibody in 100 μl PBS. Store overnight at 4° C. -   2. Remove unbound HA antibody from wells by inverting plate. Wash     plate with dH₂O. Pat the plate on a paper towel to remove excess     liquid. -   3. Add 150 μl Blocking Buffer to each well. Incubate, with shaking,     for 30 min at room temperature. -   4. Wash plate 4× with TBS-T. -   5. Dilute lysate in PBS (1.5 μg lysate/100 μl PBS). -   6. Add 100 μl of diluted lysate to each well. Shake at room     temperature for 1 hr. -   7. Wash as in step 4. -   8. Add 50 μl of 2× kinase Buffer to ELISA plate containing captured     pyk2-HA. -   9. Add 25 μL of 400 μM test compound in 4% DMSO to each well. For     control wells use 4% DMSO alone. -   10. Add 25 μL of 0.5 M EDTA to negative control wells. -   11. Add 25 μl of 20 μM ATP to all wells. Incubate, with shaking, for     10 minutes. -   12. Stop reaction by adding 25 μl 500 mM EDTA (pH 8.0) to all wells. -   13. Wash as in step 4. -   14. Add 100 μL HRP conjugated anti-Ptyr diluted 1:6000 in Antibody -    Dilution Buffer to each well. Incubate, with shaking, for 1 hr. at     room temperature. -   15. Wash plate 3× with TBST and 1× with PBS. -   16. Add 100 μL of ABST solution to each well. -   17. If necessary, stop the development reaction by adding 20 μL 10%     SDS to each well. -   18. Read plate on ELISA reader with test filter at 410 nM and     reference filter at 630 nM.

FGFR1 Bioassay

This assay is used to measure the in vitro kinase activity of FGF1-R in an ELISA assay.

Materials and Reagents:

-   1. Costar 96-well Elisa plates (Corning Catalog # 3369). -   2. Poly(Glu-Tyr) (Sigma Catalog # P0275). -   3. PBS (Gibco Catalog # 450–1300EB) -   4. 50 mM Hepes Buffer Solution. -   5. Blocking Buffer (5% BSA/PBS). -   6. Purified GST-FGFR1 (SUGEN, Inc.) -   7. Kinase Dilution Buffer. -    Mix 500 μl 1M Hepes (GIBCO), 20 μl 5% BSA/PBS, 10 μl 100 mM sodium     orthovanadate and 50 μl 5M NaCl. -   8. 10 mM ATP -   9. ATP/MnCl₂ phosphorylation mix: mix 20 μL ATP, 400 μL 1M MnCl₂ and     9.56 ml dH₂O. -   10. NUNC 96-well V bottom polypropylene plates (Applied Scientific     Catalog # AS-72092). -   11. 0.5M EDTA. -   12. 0.05% TBST -    Add 500 μL TWEEN to 1 liter TBS. -   13. Rabbit polyclonal anti-phosphotyrosine serum (SUGEN, Inc.). -   14. Goat anti-rabbit IgG peroxidase conjugate (Biosource, Catalog #     ALI0404). -   15. ABTS Solution. -   16. ABTS/H₂O₂ solution.     Procedure: -   1. Coat Costar 96 well ELISA plates with 1 μg per well Poly(Glu,Tyr)     in 100 μl PBS. Store overnight at 4° C. -   2. Wash coated plates once with PBS. -   3. Add 150 μL of 5% BSA/PBS Blocking Buffer to each well. Incubate,     with shaking, for 1 hr.room temperature. -   4. Wash plate 2× with PBS, then once with 50 mM Hepes. Pat plates on     a paper towel to remove excess liquid and bubbles. -   5. Add 25 μL of 0.4 mM test compound in 4% DMSO or 4% DMSO alone     (controls) to plate. -   6. Dilute purified GST-FGFR1 in Kinase Dilution Buffer (5 ng     kinase/50 ul KDB/well). -   7. Add 50 μL of diluted kinase to each well. -   8. Start kinase reaction by adding 25 μl/well of freshly prepared     ATP/Mn++ (0.4 ml 1M MnCl₂, 40 μL 10 mM ATP, 9.56 ml dH₂O), freshly     prepared). -   9. This is a fast kinase reaction and must be stopped with 25 μL of     0.5M EDTA in a manner similar to the addition of ATP. -   10. Wash plate 4× with fresh TBST. -   11. Make up Antibody Dilution Buffer: Per 50 ml: -    Mix 5 ml of 5% BSA, 250 μl of 5% milk and 50 μl of 100 mM sodium     vanadate, bring to final volume with 0.05% TBST. -   12. Add 100 μl per well of anti-phosphotyrosine (1:10000 dilution in     ADB). Incubate, with shaking for 1 hr. at room temperature. -   13. Wash as in step 10. -   14. Add 100 μl per well of Biosource Goat anti-rabbit IgG peroxidase     conjugate (1:6000 dilution in ADB). Incubate, with shaking for 1 hr.     at room temperature. -   15. Wash as in step 10 and then with PBS to remove bubbles and     excess TWEEN. -   16. Add 100 μl of ABTS/H₂O₂ solution to each well. -   17. Incubate, with shaking, for 10 to 20 minutes. Remove any     bubbles. -   18. Read assay on Dynatech MR7000 elisa reader: test filter at 410     nM, reference filtrate 630 nM.

EGFR Bioassay

This assay is used to the in vitro kinase activity of FGF1-R in an ELISA assay.

Materials and Reagents:

1. Corning 96-well Elisa plates.

2. SUMO1 monoclonal anti-EGFR antibody (SUGEN, Inc.).

3. PBS

4. TBST Buffer

5. Blocking Buffer: for 100 ml, mix 5.0 g Carnation Instant Non-fat Milk® with 100 ml of PBS.

6. A431 cell lysate (SUGEN, Inc.).

7. TBS Buffer:

8. TBS+10% DMSO: for 1 L, mix 1.514 g TRIS, 2.192 g NaCl and 25 ml DMSO; bring to 1 liter total volume with dH₂O.

9. ATP (Adenosine-5′-triphosphate, from Equine muscle, Sigma Cat. No. A-5394), 1.0 mM solution in dH₂O. This reagent should be made up immediately prior to use and kept on ice.

10. 1.0 mM MnCl₂.

11. ATP/MnCl₂ phosphorylation mix: to make 10 ml, mix 300 μl of 1 mM ATP, 500 μl MnCl₂ and 9.2 ml dH₂O. Prepare just prior to use, keep on ice.

12. NUNC 96-well V bottom polypropylene plates.

13. EDTA.

14. Rabbit polyclonal anti-phosphotyrosine serum (SUGEN, Inc.).

15. Goat anti-rabbit IgG peroxidase conjugate (Biosource Cat. No. ALI0404).

16. ABTS.

17. 30% Hydrogen peroxide.

18. ABTS/H₂O₂.

19. 0.2 M HCl.

Procedure:

1. Coat Corning 96 well ELISA plates with 0.5 μg SUMO1 in 100 μl PBS per well, store overnight at 4° C.

2. Remove unbound SUMO1 from wells by inverting plate to remove liquid. Wash 1× with dH₂O. Pat the plate on a paper towel to remove excess liquid.

3. Add 150 μl of Blocking Buffer to each well. Incubate, with shaking, for 30 min. at room temperature.

4. Wash plate 3× with deionized water, then once with TBST. Pat plate on a paper towel to remove excess liquid and bubbles.

5. Dilute lysate in PBS (7 μg lysate/100 μl PBS).

6. Add 100 μl of diluted lysate to each well. Shake at room temperature for 1 hr.

7. Wash plates as in 4, above.

8. Add 120 μl TBS to ELISA plate containing captured EGFR.

9. Dilute test compound 1:10 in TBS, place in well

10. Add 13.5 μl diluted test compound to ELISA plate. To control wells, add 13.5 μl TBS in 10% DMSO.

11. Incubate, with shaking, for 30 minutes at room temperature.

12. Add 15 μl phosphorylation mix to all wells except negative control well. Final well volume should be approximately 150 μl with 3 μM ATP/5 mM MnCl₂ final concentration in each well. Incubate with shaking for 5 minutes.

13. Stop reaction by adding 16.5 μl of EDTA solution while shaking. Shake for additional 1 min.

14. Wash 4× with deionized water, 2× with TBST.

15. Add 100 μl anti-phosphotyrosine (1:3000 dilution in TBST) per well. Incubate, with shaking, for 30–45 min. at room temperature.

16. Wash as in 4, above.

17. Add 100 μl Biosource Goat anti-rabbit IgG peroxidase conjugate (1:2000 dilution in TBST) to each well. Incubate with shaking for 30 min. at room temperature.

18. Wash as in 4, above.

19. Add 100 μl of ABTS/H₂O₂ solution to each well.

20. Incubate 5 to 10 minutes with shaking. Remove any bubbles.

21. If necessary, stop reaction by adding 100 μl 0.2 M HCl per well.

22. Read assay on Dynatech MR7000 ELISA reader: test filter at 410 nM, reference filter at 630 nM.

PDGFR Bioassay

This assay is used to the in vitro kinase activity of FGF1-R in an ELISA assay.

Materials and Reagents:

1. Corning 96-well Elisa plates

2. 28D4C10 monoclonal anti-PDGFR antibody (SUGEN, Inc.).

3. PBS.

4. TBST Buffer.

5. Blocking Buffer (same as for EGFR bioassay).

6. PDGFR-P expressing NIH 3T3 cell lysate (SUGEN, Inc.).

7. TBS Buffer.

8. TBS+10% DMSO.

9. ATP.

10. MnCl₂.

11. Kinase buffer phosphorylation mix: for 10 ml, mix 250 μl 1M TRIS, 200 μt 5M NaCl, 100 μl 1M MnCl₂ and 50μl 100 mM Triton X-100 in enough dH₂O to make 10 ml.

12. NUNC 96-well V bottom polypropylene plates.

13. EDTA.

14. Rabbit polyclonal anti-phosphotyrosine serum (SUGEN,Inc.).

15. Goat anti-rabbit IgG peroxidase conjugate (Biosource Cat. No. ALI0404).

16. ABTS.

17. Hydrogen peroxide, 30% solution.

18. ABTS/H₂O₂.

19. 0.2 M HCl.

Procedure:

1. Coat Corning 96 well ELISA plates with 0.5 μg 28D4C10 in 100 μl PBS per well, store overnight at 4° C.

2. Remove unbound 28D4C10 from wells by inverting plate to remove liquid. Wash 1× with dH₂O. Pat the plate on a paper towel to remove excess liquid.

3. Add 150 μl of Blocking Buffer to each well. Incubate for 30 min. at room temperature with shaking.

4. Wash plate 3× with deionized water, then once with TBST. Pat plate on a paper towel to remove excess liquid and bubbles.

5. Dilute lysate in HNTG (10 μg lysate/100 μl HNTG).

6. Add 100 μl of diluted lysate to each well. Shake at room temperature for 60 min.

7. Wash plates as described in Step 4.

8. Add 80 μl working kinase buffer mix to ELISA plate containing captured PDGFR.

9. Dilute test compound 1:10 in TBS in 96-well polypropylene plates.

10. Add 10 μl diluted test compound to ELISA plate. To control wells, add 10 μl TBS+10% DMSO. Incubate with shaking for 30 minutes at room temperature.

11. Add 10 μl ATP directly to all wells except negative control well (final well volume should be approximately 100 μl with 20 μM ATP in each well.) Incubate 30 minutes with shaking.

12. Stop reaction by adding 10 μl of EDTA solution to each well.

13. Wash 4× with deionized water, twice with TBST.

14. Add 100 μl anti-phosphotyrosine (1:3000 dilution in TBST) per well. Incubate with shaking for 30–45 min. at room temperature.

15. Wash as in Step 4.

16. Add 100 μl Biosource Goat anti-rabbit IgG peroxidase conjugate (1:2000 dilution in TBST) to each well. Incubate with shaking for 30 min. at room temperature.

17. Wash as in Step 4.

18. Add 100 μl of ABTS/H₂O₂ solution to each well.

19. Incubate 10 to 30 minutes with shaking. Remove any bubbles.

20. If necessary stop reaction with the addition of 100 μl 0.2 M HCl per well.

21. Read assay on Dynatech MR7000 ELISA reader with test filter at 410 nM and reference filter at 630 nM.

Cellular Her-2 Kinase Assay

This assay is used to measure HER-2 kinase activity in whole cells in an ELISA format.

Materials and Reagents:

-   1. DMEM (GIBCO Catalog #11965–092). -   2. Fetal Bovine Serum (FBS, GIBCO Catalog #16000–044), heat     inactivated in a water bath for 30 min. at 56° C. -   3. Trypsin (GIBCO Catalog #25200–056). -   4. L-Glutamine (GIBCO Catalog #25030–081) -   5. HEPES (GIBCO Catalog #15630–080). -   6. Growth Media -    Mix 500 ml DMEM, 55 ml heat inactivated FBS, 10 ml HEPES and 5.5 ml     L-Glutamine. -   7. Starve Media -    Mix 500 ml DMEM, 2.5 ml heat inactivated FBS, 10 ml HEPES and 5.5     ml L-Glutamine. -   8. PBS. -   9. Flat Bottom 96-well Tissue Culture Micro Titer Plates (Corning     Catalog # 25860). -   10. 15 cm Tissue Culture Dishes (Corning Catalog #08757148). -   11. Corning 96-well ELISA Plates. -   12. NUNC 96-well V bottom polypropylene plates. -   13. Costar Transfer Cartridges for the Transtar 96 (Costar Catalog     #7610). -   14. SUMO 1: monoclonal anti-EGFR antibody (SUGEN, Inc.). -   15. TBST Buffer. -   16. Blocking Buffer: 5% Carnation Instant Milk® in PBS. -   17. EGF Ligand: EGF-201, Shinko American, Japan. Suspend powder in     100 uL of 10 mM HCl. Add 100 uL 10 mM NaOH. Add 800 uL PBS and     transfer to an Eppendorf tube, store at −20° C. until ready to use. -   18. HNTG Lysis Buffer -    For Stock 5× HNTG, mix 23.83 g Hepes, 43.83 g NaCl, 500 ml glycerol     and 100 ml Triton X-100 and enough dH₂O to make 1 L of total     solution. -    For 1× HNTG*, mix 2 ml HNTG, 100 μL 0.1M Na₃VO₄, 250 μL 0.2M     Na₄P₂O₇ and 100 μL EDTA. -   19. EDTA. -   20. Na₃VO₄. To make stock solution, mix 1.84 g Na₃VO₄ with 90 ml     dH₂O. Adjust pH to 10. Boil in microwave for one minute (solution     becomes clear). Cool to room temperature. Adjust pH to 10. Repeat     heating/cooling cycle until pH remains at 10. -   21. 200 mM Na₄P₂O₇. -   22. Rabbit polyclonal antiserum specific for phosphotyrosine     (anti-Ptyr antibody, SUGEN, Inc.). -   23. Affinity purified antiserum, goat anti-rabbit IgG antibody,     peroxidase conjugate (Biosource Cat # ALI0404). -   24. ABTS Solution. -   25. 30% Hydrogen peroxide solution. -   26. ABTS/H₂O₂. -   27. 0.2 M HCl.     Procedure: -   1. Coat Corning 96 well ELISA plates with SUMO1 at 1.0 ug per well     in PBS, 100 ul final volume/well. Store overnight at 4° C. -   2. On day of use, remove coating buffer and wash plate 3 times with     dH₂O and once with TBST buffer. All washes in this assay should be     done in this manner, unless otherwise specified. -   3. Add 100 ul of Blocking Buffer to each well. Incubate plate, with     shaking, for 30 min. at room temperature. Just prior to use, wash     plate. -   4. Use EGFr/HER-2 chimera/3T3-C7 cell line for this assay. -   5. Choose dishes having 80–90% confluence. Collect cells by     trypsinization and centrifuge at 1000 rpm at room temperature for 5     min. -   6. Resuspend cells in starve medium and count with trypan blue.     Viability above 90% is required. Seed cells in starve medium at a     density of 2,500 cells per well, 90 ul per well, in a 96 well     microtiter plate. Incubate seeded cells overnight at 37° under 5%     CO₂. -   7. Start the assay two days after seeding. -   8. Test compounds are dissolved in 4% DMSO. Samples are then further     diluted directly on plates with starve-DMEM. Typically, this     dilution will be 1:10 or greater. All wells are then transferred to     the cell plate at a further 1:10 dilution (10μl sample and media     into 90 μl of starve media. The final DMSO concentration should be     1% or lower. A standard serial dilution may also be used. -   9. Incubate under 5% CO₂ at 37° C. for 2 hours. -   10. Prepare EGF ligand by diluting stock EGF (16.5 uM) in warm DMEM     to 150 nM. -   11. Prepare fresh HNTG* sufficient for 100 ul per well; place on     ice. -   12. After 2 hour incubation with test compound, add prepared EGF     ligand to cells, 50 ul per well, for a final concentration of 50 nM.     Positive control wells receive the same amount of EGF. Negative     controls do not receive EGF. Incubate at 37° C. for 10 min. -   13. Remove test compound, EGF, and DMEM. Wash cells once with PBS. -   14. Transfer HNTG* to cells, 100 ul per well. Place on ice for 5     minutes. Meanwhile, remove blocking buffer from ELISA plate and     wash. -   15. Scrape cells from plate with a micropipettor and homogenize cell     material by repeatedly aspirating and dispensing the HNTG* lysis     buffer. Transfer lysate to a coated, blocked, washed ELISA plate.     Or, use a Costar transfer cartridge to transfer lysate to the plate. -   16. Incubate, with shaking, at room temperature for 1 hr. -   17. Remove lysate, wash. Transfer freshly diluted anti-Ptyr antibody     (1:3000 in TBST) to ELISA plate, 100 ul per well. -   18. Incubate, with shaking, at room temperature, for 30 min. -   19. Remove anti-Ptyr antibody, wash. Transfer freshly diluted     BIOSOURCE antibody to ELISA plate(1:8000 in TBST, 100 ul per well). -   20. Incubate, with shaking, at room temperature for 30 min. -   21. Remove BIOSOURCE antibody, wash. Transfer freshly prepared     ABTS/H₂O₂ solution to ELISA plate, 100 ul per well. -   22. Incubate, with shaking, for 5–10 minutes. Remove any bubbles. -   23. Stop reaction with the addition of 100 ul of 0.2 M HCl per well. -   24. Read assay on Dynatech MR7000 ELISA reader with test filter set     at 410 nM and reference filter at 630 nM.

CDK2/CYCLIN A Assay

This assay is used to measure the in vitro serine/threonine kinase activity of human cdk2/cyclin A in a Scintillation Proximity Assay (SPA).

Materials and Reagents.

-   1. Wallac 96-well polyethylene terephthalate (flexi) plates (Wallac     Catalog # 1450–401). -   2. Amersham Redivue [γ³³P] ATP (Amersham catalog #AH 9968). -   3. Amersham streptavidin coated polyvinyltoluene SPA beads (Amersham     catalog #RPNQ0007). The beads should be reconstituted in PBS without     magnesium or calcium, at 20 mg/ml. -   4. Activated cdk2/cyclin A enzyme complex purified from Sf9 cells     (SUGEN, Inc.). -   5. Biotinylated peptide substrate (Debtide). Peptide     biotin-X-PKTPKKAKKL is dissolved in dH₂O at a concentration of 5     mg/ml. -   6. Peptide/ATP Mixture: for 10 ml, mix 9.979 ml dH₂O, 0.00125 ml     “cold” ATP, 0.010 ml Debtide and 0.010 ml γ³³P ATP. The ultimate     concentration per well will be 0.5 μM “cold” ATP, 0.1 μg Debtide and     0.2 μCi γ³³ P ATP. -   7. Kinase buffer: for 10 ml, mix 8.85 ml dH₂O, 0.625 ml TRIS(PH     7.4), 0.25 ml 1M MgCl₂, 0.25 ml 10% NP40 and 0.025 ml 1M DTT, added     fresh just prior to use. -   8. 10 mM ATP in dH₂O. -   9. 1M Tris, pH adjusted to 7.4 with HCl. -   10. 1M MgCl₂. -   11. 1M DTT. -   12. PBS (Gibco Catalog # 14190–144). -   13. 0.5M EDTA. -   14. Stop solution: For 10 ml, mix 9.25 ml PBS, 0.005 ml 100 mM ATP,     0.1 ml 0.5 M EDTA, 0.1 ml 10% Triton X-100 and 1.25 ml of 20 mg/ml     SPA beads.     Procedure: -   1. Prepare solutions of test compounds at 5× the desired final     concentration in 5% DMSO. Add 10 ul to each well. For negative     controls, use 10 ul 5% DMSO alone in wells. -   2. Dilute 5 μl of cdk2/cyclin A solution with 2.1 ml 2× kinase     buffer. -   3. Add 20 ul enzyme to each well. -   4. Add 10 μL of 0.5 M EDTA to the negative control wells. -   5. To start kinase reaction, add 20 μL of peptide/ATP mixture to     each well. Incubate for 1 hr. without shaking. -   6. Add 200 μl stop solution to each well. -   7. Hold at least 10 min. -   8. Spin plate at approx. 2300 rpm for 3–5 min. -   9. Count plate using Trilux or similar reader.

Met Transphosphorylation Assay

This assay is used to measure phosphotyrosine levels on a poly(glutamic acid:tyrosine (4:1)) substrate as a means for identifying agonists/antagonists of met transphosphorylation of the substrate.

Materials and Reagents:

-   1. Corning 96-well Elisa plates, Corning Catalog # 25805–96. -   2. Poly(glu, tyr) 4:1, Sigma, Cat. No; P 0275. -   3. PBS, Gibco Catalog # 450–1300EB -   4. 50 mM HEPES -   5. Blocking Buffer: Dissolve 25 g Bovine Serum Albumin, Sigma Cat.     No A-7888, in 500 ml PBS, filter through a 4 μm filter. -   6. Purified GST fusion protein containing the Met kinase domain,     Sugen, Inc. -   7. TBST Buffer. -   8. 10% aqueous (MilliQue H₂O) DMSO. -   9. 10 mM aqueous (dH₂O) Adenosine-5′-triphosphate, Sigma Cat. No.     A-5394. -   10. 2× Kinase Dilution Buffer: for 100 ml, mix 10 mL 1M HEPES at pH     7.5 with 0.4 mL 5% BSA/PBS, 0.2 mL 0.1 M sodium orthovanadate and 1     mL 5M sodium chloride in 88.4 mL dH₂O. -   11. 4× ATP Reaction Mixture: for 10 mL, mix 0.4 mL 1 M manganese     chloride and 0.02 mL 0.1 M ATP in 9.56 mL dH₂O. -   12. 4× Negative Controls Mixture: for 10 mL, mix 0.4 mL 1 M     manganese chloride in 9.6 mL dH₂O. -   13. NUNC 96-well V bottom polypropylene plates, Applied Scientific     Catalog # S-72092 -   14. 500 mM EDTA. -   15. Antibody Dilution Buffer: for 100 mL, mix 10 mL 5% BSA/PBS, 0.5     mL 5% Carnation Instant Milk® in PBS and 0.1 mL 0.1 M sodium     orthovanadate in 88.4 mL TBST. -   16. Rabbit polyclonal antophosphotyrosine antibody, Sugen, Inc. -   17. Goat anti-rabbit horseradish peroxidase conjugated antibody,     Biosource, Inc. -   18. ABTS Solution: for 1 L, mix 19.21 g citric acid, 35.49 g Na₂HPO₄     and 500 mg ABTS with sufficient dH₂O to make 1 L. -   19. ABTS/H₂O₂: mix 15 mL ABST solution with 2 μL H₂O₂ five minutes     before use. -   20. 0.2 M HCl     Procedure: -   1. Coat ELISA plates with 2 μg Poly(Glu-Tyr) in 100 μL PBS, store     overnight at 4° C. -   2. Block plate with 150 μL of 5% BSA/PBS for 60 min. -   3. Wash plate twice with PBS, once with 50 mM Hepes buffer pH 7.4. -   4. Add 50 μl of the diluted kinase to all wells. (Purified kinase is     diluted with Kinase Dilution Buffer. Final concentration should be     10 ng/well.) -   5. Add 25 μL of the test compound (in 4% DMSO) or DMSO alone (4% in     dH₂O) for controls to plate. -   6. Incubate the kinase/compound mixture for 15 minutes. -   7. Add 25 μL of 40 mM MnCl₂ to the negative control wells. -   8. Add 25 μL ATP/MnCl₂ mixture to the all other wells (except the     negative controls). Incubate for 5 min. -   9. Add 25 μL 500 mM EDTA to stop reaction. -   10. Wash plate 3× with TBST. -   11. Add 100 μL rabbit polyclonal anti-Ptyr diluted 1:10,000 in     Antibody Dilution Buffer to each well. Incubate, with shaking, at     room temperature for one hour. -   12. Wash plate 3× with TBST. -   13. Dilute Biosource HRP conjugated anti-rabbit antibody 1:6,000 in     Antibody Dilution buffer. Add 100 μL per well and incubate at room     temperature, with shaking, for one hour. -   14. Wash plate 1× with PBS. -   15. Add 100 μl of ABTS/H₂O₂ solution to each well. -   16. If necessary, stop the development reaction with the addition of     100 μl of 0.2M HCl per well. -   17. Read plate on Dynatech MR7000 elisa reader with the test filter     at 410 nM and the reference filter at 630 nM.

IGF-1 Transphosphorylation Assay

This assay is used to measure the phosphotyrosine level in poly(glutamic acid:tyrosine)(4:1) for the identification of agonists/antagonists of gst-IGF-1 transphosphorylation of a substrate.

Materials and Reagents:

-   1. Corning 96-well Elisa plates. -   2. Poly (Glu-tyr) (4:1), Sigma Cat. No. P 0275. -   3. PBS, Gibco Catalog # 450–1300EB. -   4. 50 mM HEPES -   5. TBB Blocking Buffer: for 1 L, mix 100 g BSA, 12.1 gTRIS (pH 7.5),     58.44 g sodium chloride and 10 mL 1% TWEEN-20. -   6. Purified GST fusion protein containing the IGF-1 kinase domain     (Sugen, Inc.) -   7. TBST Buffer: for 1 L, mix 6.057 g Tris, 8.766 g sodium chloride     and 0.5 ml TWEEN-20 with enough dH₂O to make 1 liter. -   8. 4% DMSO in Milli-Q H₂O. -   9. 10 mM ATP in dH₂O. -   10. 2× Kinase Dilution Buffer: for 100 mL, mix 10 mL 1 M HEPES (pH     7.5), 0.4 mL 5% BSA in dH₂O, 0.2 mL 0.1 M sodium orthovanadate and 1     mL 5 M sodium chloride with enough dH₂O to make 100 mL. -   11. 4× ATP Reaction Mixture: for 10 mL, mix 0.4 mL 1 M MnCl₂ and     0.008 mL 0.01 M ATP and 9.56 mL dH₂O. -   12. 4× Negative Controls Mixture: mix 0.4 mL 1 M manganese chloride     in 9.60 mL dH₂O. -   13. NUNC 96-well V bottom polypropylene plates. -   14. 500 mM EDTA in dH₂O. -   15. Antibody Dilution Buffer: for 100 mL, mix 10 mL 5% BSA in PBS,     0.5 mL 5% Carnation Instant Non-fat Milk® in PBS and 0.1 mL 0.1 M     sodium orthovanadate in 88.4 mL TBST. -   16. Rabbit Polyclonal antiphosphotyrosine antibody, Sugen, Inc. -   17. Goat anti-rabbit HRP conjugated antibody, Biosource. -   18. ABTS Solution. -   20. ABTS/H₂O₂: mix 15 mL ABTS with 2 μL H₂O₂ 5 minutes before using. -   21. 0.2 M HCl in dH₂O.     Procedure: -   1. Coat ELISA plate with 2.0 μg /well Poly(Glu, Tyr) 4:1 (Sigma     P0275) in 100 μl PBS. Store plate overnight at 4° C. -   2. ash plate once with PBS. -   3. Add 100 μl of TBB Blocking Buffer to each well. Incubate plate     for 1 hour with shaking at room temperature. -   4. Wash plate once with PBS, then twice with 50 mM Hepes buffer pH     7.5. -   5. Add 25 μL of test compound in 4% DMSO (obtained by diluting a     stock solution of 10 mM test compound in 100% DMSO with dH₂O) to     plate. -   6. Add 10.0 ng of gst-IGF-1 kinase in 50 μl Kinase Dilution Buffer)     to all wells. -   7. Start kinase reaction by adding 25 μl 4× ATP Reaction Mixture to     all test wells and positive control wells. Add 25μl 4× Negative     Controls Mixture to all negative control wells. Incubates for 10     minutes with shaking at room temperature. -   8. Add 25μl 0.5M EDTA (pH 8.0) to all wells. -   9. Wash plate 4× with TBST Buffer. -   10. Add rabbit polyclonal anti-phosphotyrosine antisera at a     dilution of 1:10,000 in 100 μl Antibody Dilution Buffer to all     wells. Incubate, with shaking, at room temperature for 1 hour. -   11. Wash plate as in step 9. -   12. Add 100 μL Biosource anti-rabbit HRP at a dilution of 1:10,000     in Antibody dilution buffer to all wells. Incubate, with shaking, at     room temperature for 1 hour. -   13. Wash plate as in step 9, follow with one wash with PBS to reduce     bubbles and excess Tween-20. -   14. Develop by adding 100 μl/well ABTS/H₂O₂ to each well. -   15. After about 5 minutes, read on ELISA reader with test filter at     410 nm and referenced filter at 630 nm.

Brdu Incorporation Assays

The following assays use cells engineered to express a selected receptor and then evaluate the effect of a compound of interest on the activity of ligand-induced DNA synthesis by determining BrdU incorporation into the DNA.

The following materials, reagents and procedure are general to each of the following BrdU incorporation assays. Variances in specific assays are noted.

Materials and Reagents:

-   1. The appropriate ligand. -   2. The appropriate engineered cells. -   3. BrdU Labeling Reagent: 10 mM, in PBS (pH 7.4)(Boehringer     Mannheim, Germany). -   4. FixDenat: fixation solution (ready to use)(Boehringer Mannheim,     Germany). -   5. Anti-BrdU-POD: mouse monoclonal antibody conjugated with     peroxidase (Boehringer Mannheim, Germany). -   6. TMB Substrate Solution: tetramnethylbenzidine (TMB, Boehringer     Mannheim, Germany). -   7. PBS Washing Solution: 1× PBS, pH 7.4. -   8. Albumin, Bovine (BSA), fraction V powder (Sigma Chemical Co.,     USA).     General Procedure: -   1. Cells are seeded at 8000 cells/well in 10% CS, 2 mM Gln in DMEM,     in a 96 well plate. Cells are incubated overnight at 37° C. in 5%     CO₂. -   2. After 24 hours, the cells are washed with PBS, and then are     serum-starved in serum free medium (0% CS DMEM with 0.1% BSA) for 24     hours. -   3. On day 3, the appropriate ligand and the test compound are added     to the cells simultaneously. The negative control wells receive     serum free DMEM with 0.1% BSA only; the positive control cells     receive the ligand but no test compound. Test compounds are prepared     in serum free DMEM with ligand in a 96 well plate, and serially     diluted for 7 test concentrations. -   4. After 18 hours of ligand activation, diluted BrdU labeling     reagent (1:100 in DMEM, 0.1% BSA) is added and the cells are     incubated with BrdU (final concentration=10 μM) for 1.5 hours. -   5. After incubation with labeling reagent, the medium is removed by     decanting and tapping the inverted plate on a paper towel. FixDenat     solution is added (50 μl/well) and the plates are incubated at room     temperature for 45 minutes on a plate shaker. -   6. The FixDenat solution is thoroughly removed by decanting and     tapping the inverted plate on a paper towel. Milk is added (5%     dehydrated milk in PBS, 200 μl/well) as a blocking solution and the     plate is incubated for 30 minutes at room temperature on a plate     shaker. -   7. The blocking solution is removed by decanting and the wells are     washed once with PBS. Anti-BrdU-POD solution (1:200 dilution in PBS,     1% BSA) is added (50 μl/well) and the plate is incubated for 90     minutes at room temperature on a plate shaker. -   8. The antibody conjugate is thoroughly removed by decanting and     rinsing the wells 5 times with PBS, and the plate is dried by     inverting and tapping on a paper towel. -   9. TMB substrate solution is added (100 μl/well) and incubated for     20 minutes at room temperature on a plate shaker until color     development is sufficient for photometric detection. -   10. The absorbance of the samples are measured at 410 mn (in “dual     wavelength” mode with a filter reading at 490 nm, as a reference     wavelength) on a Dynatech ELISA plate reader.

EGF-Induced BrdU Incorporation Assay

Materials and Reagents:

-   1. Mouse EGF, 201 (Toyobo Co., Ltd., Japan). -   2. 3T3/EGFRc7.

EGF-Induced Her-2-driven BrdU Incorporation Assay

Materials and Reagents:

-   1. Mouse EGF, 201 (Toyobo Co., Ltd., Japan). -   2. 3T3/EGFr/Her2/EGFr (EGFr with a Her-2 kinase domain).

EGF-Induced Her-4-driven BrdU Incorporation Assay

Materials and Reagents:

-   1. Mouse EGF, 201 (Toyobo Co., Ltd., Japan). -   2. 3T3/EGFr/Her4/EGFr (EGFr with a Her-4 kinase domain).

PDGF-Induced BrdU Incorporation Assay

Materials and Reagents:

-   1. Human PDGF B/B (Boehringer Mannheim, Germany). -   2. 3T3/EGFRc7.

FGF-Induced BrdU Incorporation Assay

Materials and Reagents:

-   1. Human FGF2/bFGF (Gibco BRL, USA). -   2. 3T3c7/EGFr

IGF1-Induced BrdU Incorporation Assay

Materials and Reagents:

-   1. Human, recombinant (G511, Promega Corp., USA) -   2. 3T3/IGF1r.

Insulin-Induced BrdU Incorporation Assay

Materials and Reagents:

-   1. Insulin, crystalline, bovine, Zinc (13007, Gibco BRL, USA). -   2. 3T3/H25.

HGF-Induced BrdU Incorporation Assay

Materials and Reagents:

-   1. Recombinant human HGF (Cat. No. 249-HG, R&D Systems, Inc. USA). -   2. BxPC-3 cells (ATCC CRL-1687).     Procedure: -   1. Cells are seeded at 9000 cells/well in RPMI 10% FBS in a 96 well     plate. Cells are incubated overnight at 37° C. in 5% CO₂. -   2. After 24 hours, the cells are washed with PBS, and then are serum     starved in 100 μl serum-free medium (RPMI with 0.1% BSA) for 24     hours. -   3. On day 3, 25 μl containing ligand (prepared at 1 μg/ml in RPMI     with 0.1% BSA; final HGF conc. is 200 ng/ml) and test compounds are     added to the cells. The negative control wells receive 25 μl     serum-free RPMI with 0.1% BSA only; the positive control cells     receive the ligand (HGF) but no test compound. Test compounds are     prepared at 5 times their final concentration in serum-free RPMI     with ligand in a 96 well plate, and serially diluted to give 7 test     concentrations. Typically, the highest final concentration of test     compound is 100 μM, and 1:3 dilutions are used (i.e. final test     compound concentration range is 0.137–100 μM). -   4. After 18 hours of ligand activation, 12.5 μl of diluted BrdU     labeling reagent (1:100 in RPMI, 0.1% BSA) is added to each well and     the cells are incubated with BrdU (final concentration is 10 μM) for     1 hour. -   5. Same as General Procedure. -   6. Same as General Procedure. -   7. The blocking solution is removed by decanting and the wells are     washed once with PBS. Anti-BrdU-POD solution (1:100 dilution in PBS,     1% BSA) is added (100 μl/well) and the plate is incubated for 90     minutes at room temperature on a plate shaker. -   8. Same as General Procedure. -   9. Same as General Procedure. -   10. Same as General Procedure.

HUV-EC-C Assay

This assay is used to measure a compound's activity against PDGF-R, FGF-R, VEGF, aFGF or Flk-1/KDR, all of which are naturally expressed by HUV-EC cells.

Day 0

1. Wash and trypsinize HUV-EC-C cells (human umbilical vein endothelial cells, (American Type Culture Collection, catalogue no. 1730 CRL). Wash with Dulbecco's phosphate-buffered saline (D-PBS, obtained from Gibco BRL, catalogue no. 14190–029) 2 times at about 1 ml/10 cm² of tissue culture flask. Trypsinize with 0.05% trypsin-EDTA in non-enzymatic cell dissociation solution (Sigma Chemical Company, catalogue no. C-1544). The 0.05% trypsin is made by diluting 0.25% trypsin/1 mM EDTA (Gibco, catalogue no. 25200–049) in the cell dissociation solution. Trypsinize with about 1 ml/25–30 cm² of tissue culture flask for about 5 minutes at 37° C. After cells have detached from the flask, add an equal volume of assay medium and transfer to a 50 ml sterile centrifuge tube (Fisher Scientific, catalogue no. 05–539–6).

2. Wash the cells with about 35 ml assay medium in the 50 ml sterile centrifuge tube by adding the assay medium, centrifuge for 10 minutes at approximately 200× g, aspirate the supernatant, and resuspend with 35 ml D-PBS. Repeat the wash two more times with D-PBS, resuspend the cells in about 1 ml assay medium/15 cm² of tissue culture flask. Assay medium consists of F12K medium (Gibco BRL, catalogue no. 21127–014) and 0.5% heat-inactivated fetal bovine serum. Count the cells with a Coulter Counter® (Coulter Electronics, Inc.) and add assay medium to the cells to obtain a concentration of 0.8–1.0×10⁵ cells/ml.

3. Add cells to 96-well flat-bottom plates at 100 μl/well or 0.8–1.0×10⁴ cells/well, incubate ˜24 h at 37° C., 5% CO₂.

Day 1

1. Make up two-fold test compound titrations in separate 96-well plates, generally 50 μM on down to 0 μM. Use the same assay medium as mentioned in day 0, step 2 above. Titrations are made by adding 90 μl/well of test compound at 200 μM (4× the final well concentration) to the top well of a particular plate column. Since the stock test compound is usually 20 mM in DMSO, the 200 μM drug concentration contains 2% DMSO.

A diluent made up to 2% DMSO in assay medium (F12K+0.5% fetal bovine serum) is used as diluent for the test compound titrations in order to dilute the test compound but keep the DMSO concentration constant. Add this diluent to the remaining wells in the column at 60 μl/well. Take 60 μl from the 120 μl of 200 μM test compound dilution in the top well of the column and mix with the 60 μl in the second well of the column. Take 60 μl from this well and mix with the 60 μl in the third well of the column, and so on until two-fold titrations are completed. When the next-to-the-last well is mixed, take 60 μl of the 120 μl in this well and discard it. Leave the last well with 60 μl of DMSO/media diluent as a non-test compound-containing control. Make 9 columns of titrated test compound, enough for triplicate wells each for: (1) VEGF (obtained from Pepro Tech Inc., catalogue no. 100–200, (2) endothelial cell growth factor (ECGF) (also known as acidic fibroblast growth factor, or aFGF) (obtained from Boehringer Mannheim Biochemica, catalogue no. 1439 600), or, (3) human PDGF B/B (1276–956, Boehringer Mannheim, Germany) and assay media control. ECGF comes as a preparation with sodium heparin.

2. Transfer 50 μl/well of the test compound dilutions to the 96-well assay plates containing the 0.8–1.0 ×10⁴ cells/100 μl/well of the HUV-EC-C cells from day 0 and incubate ˜2 h at 37° C., 5% CO₂.

3. In triplicate, add 50 μl/well of 80 μg/ml VEGF, 20 ng/ml ECGF, or media control to each test compound condition. As with the test compounds, the growth factor concentrations are 4× the desired final concentration. Use the assay media from day 0 step 2 to make the concentrations of growth factors. Incubate approximately 24 hours at 37° C., 5% CO₂. Each well will have 50 μl test compound dilution, 50 μl growth factor or media, and 100 μl cells, which calculates to 200 μl/well total. Thus the 4× concentrations of test compound and growth factors become 1× once everything has been added to the wells.

Day 2

1. Add ³H-thymidine (Amersham, catalogue no. TRK-686) at 1 μCi/well (10 μ/well of 100 μCi/ml solution made up in RPMI media +10% heat-inactivated fetal bovine serum) and incubate ˜24 h at 37° C., 5% CO₂. RPMI is obtained from Gibco BRL, catalogue no. 11875–051.

Day 3

1. Freeze plates overnight at −20° C.

Day 4

Thaw plates and harvest with a 96-well plate harvester (Tomtec Harvester 965) onto filter mats (Wallac, catalogue no. 1205–401), read counts on a Wallac Betaplate™ liquid scintillation counter.

Bioassays which have been or can be used to evaluate compounds are described in detail below. Compounds 1–9 were tested and found active in flkGST, FGFR1 and PDGF assays.

In Vivo Animal Models Xenograft Animal Models

The ability of human tumors to grow as xenografts in athymic mice (e.g., Balb/c, nu/nu) provides a useful in vivo model for studying the biological response to therapies for human tumors. Since the first successful xenotransplantation of human tumors into athymic mice, (Rygaard and Povlsen, 1969, Acta Pathol. Microbial. Scand. 77:758–760), many different human tumor cell lines (e.g., mammary, lung, genitourinary, gastro-intestinal, head and neck, glioblastoma, bone, and malignant melanomas) have been transplanted and successfully grown in nude mice. The following assays may be used to determine the level of activity, specificity and effect of the different compounds of the present invention. Three general types of assays are useful for evaluating compounds: cellular/catalytic, cellular/biological and in vivo. The object of the cellular/catalytic assays is to determine the effect of a compound on the ability of a TK to phosphorylate tyrosines on a known substrate in a cell. The object of the cellular/biological assays is to determine the effect of a compound on the biological response stimulated by a TK in a cell. The object of the in vivo assays is to determine the effect of a compound in an animal model of a particular disorder such as cancer.

Suitable cell lines for subcutaneous xenograft experiments include C6 cells (glioma, ATCC # CCL 107), A375 cells (melanoma, ATCC # CRL 1619), A431 cells (epidermoid carcinoma, ATCC # CRL 1555), Calu 6 cells (lung, ATCC # HTB 56), PC3 cells (prostate, ATCC # CRL 1435), SKOV3TP5 cells and NIH 3T3 fibroblasts genetically engineered to overexpress EGFR, PDGFR, IGF-1R or any other test kinase. The following protocol can be used to perform xenograft experiments:

Female athymic mice (BALB/c, nu/nu) are obtained from Simonsen Laboratories (Gilroy, Calif.). All animals are maintained under clean-room conditions in Micro-isolator cages with Alpha-dri bedding. They receive sterile rodent chow and water ad libitum.

Cell lines are grown in appropriate medium (for example, MEM, DMEM, Ham's F10, or Ham's F12 plus 5%–10% fetal bovine serum (FBS) and 2 mM glutamine (GLN)). All cell culture media, glutamine, and fetal bovine serum are purchased from Gibco Life Technologies (Grand Island, N.Y.) unless otherwise specified. All cells are grown in a humid atmosphere of 90–95% air and 5–10% CO₂ at 37° C. All cell lines are routinely subcultured twice a week and are negative for mycoplasma as determined by the Mycotect method (Gibco).

Cells are harvested at or near confluency with 0.05% Trypsin-EDTA and pelleted at 450×g for 10 min. Pellets are resuspended in sterile PBS or media (without FBS) to a particular concentration and the cells are implanted into the hindflank of the mice (8–10 mice per group, 2–10×10⁶ cells/animal). Tumor growth is measured over 3 to 6 weeks using venier calipers. Tumor volumes are calculated as a product of length×width×height unless otherwise indicated. P values are calculated using the Students t-test. Test compounds in 50–100 μL excipient (DMSO, or VPD:D5W) can be delivered by IP injection at different concentrations generally starting at day one after implantation.

Tumon Invasion Model

The following tumor invasion model has been developed and may be used for the evaluation of therapeutic value and efficacy of the compounds identified to selectively inhibit KDR/FLK-1 receptor.

Procedure

8 week old nude mice (female) (Simonsen, Inc.) are used as experimental animals. Implantation of tumor cells can be performed in a laminar flow hood. For anesthesia, Xylazine/Ketamine Cocktail (100 mg/kg ketamine and 5 mg/kg Xylazine) are administered intraperitoneally. A midline incision is done to expose the abdominal cavity (approximately 1.5 cm in length) to inject 10⁷ tumor cells in a volume of 100 μl medium. The cells are injected either into the duodenal lobe of the pancreas or under the serosa of the colon. The peritoneum and muscles are closed with a 6–0 silk continuous suture and the skin is closed by using wound clips. Animals are observed daily.

Analysis

After 2–6 weeks, depending on gross observations of the animals, the mice are sacrificed, and the local tumor metastases to various organs (lung, liver, brain, stomach, spleen, heart, muscle) are excised and analyzed (measurement of tumor size, grade of invasion, immunochemistry, in situ hybridization determination, etc.).

C-KIT Assay

This assay is used to detect the level of c-kit tyrosine phosphorylation.

MO7E (human acute myeloid leukemia) cells are serum starved overnight in 0.1% serum. Cells are pre-treated with the compound (concurrent with serum starvation), prior to ligand stimulation. Cells are stimulated with 250 ng/ml rh-SCF for 15 minutes. Following stimulation, cells were lysed and immunoprecipitated with an anti-c-kit antibody. Phosphotyrosine and protein levels were determined by Western blotting.

MTT Proliferation Assay

MO7E cells are serum starved and pre-treated with compound as described for the phosphorylation experiments. Cells areplated @ 4×10⁵ cells/well in a 96 well dish, in 100 μl RPMI+10% serum. rh-SCF (100 ng/mL) is added and the plate is incubated for 48 hours. After 48 hours, 10 μl of 5 mg/ml MTT [3-(4, 5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide) is added and allowed to incubate for 4 hours. Acid isopropanol (100 μl of 0.04N HCl in isopropanol) is added and the optical density was measured at a wavelength of 550 nm.

Apoptosis Assay

MO7E cells are incubated +/− SCF and +/− compound in 10% FBS with rh-GM-CSF(10 ng/mL) and rh-IL-3 (10 ng/mL). Samples are assayed at 24 and 48 hours. To measure activated caspase-3, samples are washed with PBS and permeabilized with ice-cold 70% ethanol. The cells are then stained with PE-conjugated polyclonal rabbit anti-active caspase-3 and analyzed by FACS. To measure cleaved PARP, samples are lysed and analyzed by western blotting with an anti-PARP antibody.

Additional Assays

Additional assays which may be used to evaluate the compounds of this invention include, without limitation, a bio-flk-1 assay, an EGF receptor-HER2 chimeric receptor assay in whole cells, a bio-src assay, a bio-lck assay and an assay measuring the phosphorylation function of raf. The protocols for each of these assays may be found in U.S. application Ser. No. 09/099,842, which is incorporated by reference, including any drawings, herein.

Measurement of Cell Toxicity

Therapeutic compounds should be more potent in inhibiting receptor tyrosine kinase activity than in exerting a cytotoxic effect. A measure of the effectiveness and cell toxicity of a compound can be obtained by determining the therapeutic index, i.e., IC₅₀/LD₅₀. IC₅₀, the dose required to achieve 50% inhibition, can be measured using standard techniques such as those described herein. LD₅₀, the dosage which results in 50% toxicity, can also be measured by standard techniques as well (Mossman, 1983, J. Immunol. Methods, 65:55–63), by measuring the amount of LDH released (Korzeniewski and Callewaert, 1983, J. Immunol. Methods, 64:313, Decker and Lohmann-Matthes, 1988, J. Imrunol. Methods, 115:61), or by measuring the lethal dose in animal models. Compounds with a large therapeutic index are preferred. The therapeutic index should be greater than 2, preferably at least 10, more preferably at least 50.

One skilled in the art would also readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent herein. The molecular complexes and the methods, procedures, treatments, molecules, specific compounds described herein are presently representative of preferred embodiments, are exemplary, and are not intended as limitations on the scope of the invention. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention are defined by the scope of the claims.

It will be readily apparent to one skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the scope and spirit of the invention.

All patents and publications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. All patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference.

The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein. Thus, for example, in each instance herein any of the terms “comprising”, “consisting essentially of” and “consisting of” may be replaced with either of the other two terms. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.

In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognize that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group. For example, if X is described as selected from the group consisting of bromine, chlorine, and iodine, claims for X being bromine and claims for X being bromine and chlorine are fully described.

Other embodiments are within the following claims. 

1. A compound of formula I:

wherein R₁ and R₂ are each independently H, or cyclopropyl, wherein the cyclopropyl group may be further substituted with one or more substituents selected from the group consisting of aryl, halogen, —OH, —OR₇, a heteroalicyclic group, and a trihaloalkyl group; R₃ and R₄ are H; R₅ is phenyl, wherein the phenyl group may be further substituted with one or more substituents selected from the group consisting of alkyl, alkoxy, halogen, —OR₇, —NR₇R₈, —NR₇C(O)R₈, aryl, —C(O)OR₇, cycloalkyl, haloalkyl, haloalkoxy, —C(O)R₇, —NR₇C(O)OR₈, —SO₂R₇, —NR₇C(O)NR₉R₈, —C(O)NR₇R₈ and —SO₂NR₇R₈; wherein at least one of R₃, R₄ and R₅ is an aryl; R₆ is H; R₇, R₈ and R₉ are independently H, alkyl, aralkyl, heterocycloalkyl or aryl, wherein the alkyl and aryl may be further substituted with one or more substituents selected from the group consisting of alkyl, aryl, trifluoroalkyl, —OH, alkoxy, amino, —NO₂ and —CN; alternatively, NR₇R₈ can form a 5–7 membered heteroalicyclic ring, a 5–6 membered heteroaryl ring, wherein the heteroalicyclic ring may further contain no more than 4 of the heteroatoms (N, O, or S), and the cyclic structure formed about NR₇R₈ may be substituted with one or more substituents selected from the group consisting of alkyl, haloalkyl, alkoxy, heteroalicylic, aryl, heteroaryl and halo; and wherein one of R₁ or R₂ is cyclopropyl; or a pharmaceutically acceptable salt thereof.
 2. A compound selected from the group consisting of: N-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-acetamide, Cyclopropyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, N-[3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]acetamide, Cyclopropyl-{3-[3-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine, 3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, Cyclopropyl-[3-(3,4-dichloro-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, 3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-benzoic acid, Cyclopropyl-{3-[4-(2-morpholin-4-yl-ethoxy)-phenyl]-imidazo[1,2-a]pyrazin-8-yl}-amine, Cyclopropyl-[3-(4-dimethylamino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, Cyclopropyl-[3-(4-phenoxy-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone, [4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-carbamic acid benzyl ester, [3-(3-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, 4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-benzoic acid, 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea, 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, or or pharmaceutically acceptable salt thereof.
 3. A compound selected from the group consisting of: Cyclopropyl-(3-phenyl-imidazo[1,2-a]pyrazin-8-yl)-amine, 3-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenol, Cyclopropyl-[3-(4-dimethylamino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-amine, 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-ethanone, [4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-carbamic acid benzyl ester, [3-(3-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, [3-(4-Amino-phenyl)-imidazo[1,2-a]pyrazin-8-yl]-cyclopropyl-amine, (R)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic acid [4-(8-cyclopropylamino -imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, (S)-2-Pyrrolidin-1-ylmethyl-pyrrolidine-1-carboxylic acid [4-(8-cyclopropylamino -imidazo[1,2-a]pyrazin-3-yl)-phenyl]-amide, 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-pyrrolidin-1-yl-propyl)-urea, 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(3-morpholin-4-yl-propyl)-urea, 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-pyrrolidin-1-yl-ethyl)-urea and 1-[4-(8-Cyclopropylamino-imidazo[1,2-a]pyrazin-3-yl)-phenyl]-3-(2-morpholin-4-yl-ethyl)-urea, or a pharmaceutically acceptable salt thereof.
 4. A pharmaceutical composition, comprising a compound or a pharmaceutically acceptable salt thereof, according to any one of claims 1, 2 and 3, and a pharmaceutically acceptable carrier or excipient. 